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Installing Naxsi On Ubuntu 14.04

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<h1 style="box-sizing: border-box; font-family: Raleway, Helvetica, Arial, sans-serif; line-height: 46px; margin: 0px 0px 8px;">
<span style="color: #990000; font-size: large;"><u>Installing Naxsi On Ubuntu</u></span></h1>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">NAXSI means <a href="http://www.hackthesec.co.in/search/label/NGINX">Nginx</a> Anti XSS & SQL Injection.</span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><br /></span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Technically, it is a third party nginx module, available as a package for many UNIX-like platforms. This module, by default, reads a small subset of simple (and readable) rules containing 99% of known patterns involved in websites vulnerabilities. For example, <, | or drop are not supposed to be part of a URI.</span></span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSLzQdKsTjvUisUW5FwxBc0AE6YGXY8HBvJRTLmhojFtRKXfi7dLFTmc0fViZfMVeLsi1oTMdDkMBUnUr_QOCXPSANUmRvvABmmkibeBS4h3nlR8iNLZN8-vDPea7dnRF2a4odPe7fiioQ/s1600/nginx_hackthesec.co.in.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhSLzQdKsTjvUisUW5FwxBc0AE6YGXY8HBvJRTLmhojFtRKXfi7dLFTmc0fViZfMVeLsi1oTMdDkMBUnUr_QOCXPSANUmRvvABmmkibeBS4h3nlR8iNLZN8-vDPea7dnRF2a4odPe7fiioQ/s1600/nginx_hackthesec.co.in.png" /></a></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><br /></span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Being very simple, those patterns may match legitimate queries, it is Naxsi's administrator duty to add specific rules that will whitelist those legitimate behaviours. The administrator can either add whitelists manually by analyzing nginx's error log, or (recommended) start the project by an intensive auto-learning phase that will automatically generate whitelisting rules regarding website's behaviour.</span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><br /></span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">In short, Naxsi behaves like a DROP-by-default firewall, the only job needed is to add required ACCEPT rules for the target website to work properly.</span></span></div>
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<b><u><span style="color: #0b5394;">Step 1A: Installing Naxsi without an existing Nginx installation</span></u></b></div>
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Should you not have Nginx installed on your server yet, you should follow this step. If you already have an existing Nginx installation, follow step 1B. Before we're going to install Naxsi, it might be smart to update our system. Do this by executing:</div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">apt-get update</span></span></pre>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Next, we can install Naxsi. Using apt-get for the install, Naxsi and its dependencies will be installed. Naxsi will automatically be started on boot.</span></span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">apt-get install nginx-naxsi</span></span></pre>
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<span style="font-family: verdana, geneva, sans-serif;"><div style="font-size: 15px; line-height: 26px;">
<b><u><span style="color: #0b5394;">Step 1B: Installing Naxsi with an existing Nginx installation</span></u></b></div>
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Step 1A cannot be followed in case Nginx is already installed, as the <b>nginx-naxsi</b> package will be <b>Nginx + Naxsi</b>. If you already have Nginx and want Naxsi on top of that, generally, replacing the <b>nginx-core</b> package with the <b>nginx-naxsi</b> package should work fine. It is smart to create a backup of preferably your whole server, and the <b>/etc/nginx/</b> directory should be backed up as well.</div>
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<span style="color: #333333;"><span style="font-size: 15px; line-height: 26px;">If possible, deploy a new server with a totally new Nginx installation using the nginx-naxsi package. If not, backup your server and type:</span></span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">apt-get install nginx-naxsi</span></span></pre>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">This should install Naxsi and replace the existing Nginx, but keep all your files.</span></span></div>
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<b><u><span style="color: #0b5394;">Step 2: Editing Naxsi settings</span></u></b></div>
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In order to enable Naxsi, open the file <b>/etc/nginx/nginx.conf:</b></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">vi /etc/nginx/nginx.conf</span></span></pre>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">and find the following section:</span></span></div>
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<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;"><span style="font-size: large;"># nginx-naxsi config
##
# Uncomment it if you installed nginx-naxsi
##

# include /etc/nginx/naxsi_core.rules;</span></pre>
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Remove the # in front of the include to load the Naxsi rules, which will enable Naxsi. After making that change, the line should look like this:</div>
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<b>include /etc/nginx/naxsi_core.rules;</b></div>
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The configuration of Naxsi can be found in <b>/etc/nginx/naxsi.rules</b>. You can see what it does and optionally change some settings, depending on your needs and the type of website(s) that you host.</div>
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After enabling Naxsi and editing the configuration, we need to enable Naxsi for our default site manually. Open /<b>etc/nginx/sites-enabled/default:</b></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">vi /etc/nginx/sites-enabled/default</span></span></pre>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">In order to enable Naxsi on this location, remove the # if present, otherwise leave the include line that way and don't add a #.</span></span></div>
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<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;"><span style="font-size: large;"># Uncomment to enable naxsi on this location
include /etc/nginx/naxsi.rules;</span></pre>
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<span style="font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><div>
<b><u><span style="color: #0b5394;">Step 3: Turning off learning mode</span></u></b></div>
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In order to let Naxsi protect your site, we need to turn off the learning mode. Open <b>/etc/nginx/naxsi.rules:</b></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">vi /etc/nginx/naxsi.rules</span></span></pre>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Find the string <b>LearningMode</b>, and place an # in front of it. That comments out the line and thus disable the learning mode in the config.</span></span></div>
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<span style="font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><div>
<b><u><span style="color: #0b5394;">Step 4: Restarting Naxsi</span></u></b></div>
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Restart Nginx for the changes to take effect:</div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">service nginx reload</span></span></pre>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">You can now see any security warnings from Naxsi in the Nginx log:</span></span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">tail -f /var/log/nginx/error.log</span></span></pre>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-size: large;"><a href="http://www.hackthesec.co.in/">www.hackthesec.co.in</a></span></pre>
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Installing Naxsi On Ubuntu 14.04

Installing Naxsi On Ubuntu NAXSI means Nginx Anti XSS & SQL Injection. Technically, it is a third party nginx module, availabl...

How Install Desktop on CentOS 7

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<h1 class="entry-title" itemprop="headline" style="background-color: white; box-sizing: border-box; font-family: Raleway, sans-serif; line-height: 1; margin: 0px 0px 16px;">
<span style="color: #990000; font-size: large;"><u>Install Desktop on CentOS</u></span></h1>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Now in this post, we will show how to install Desktop on CentOS 7.</span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">As a linux user , you should be aware that in Linux World we have many Desktop environment available. Some of them, we are listing down.</span></span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEha79_E-NUWn8EVF2mDRFLgI5LFPWbPUXjxgUuE3FL9jBq06rnFq_X3ItKbIYcJIHJO0QRNeOKh8_t_9314hpuQqKm6g_0RjKAnTK2AhN83DjhgLZnacV5lZPCH39lif-9Q9svBzsw7qw-k/s1600/centos7_www.hackthesec.co.in.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEha79_E-NUWn8EVF2mDRFLgI5LFPWbPUXjxgUuE3FL9jBq06rnFq_X3ItKbIYcJIHJO0QRNeOKh8_t_9314hpuQqKm6g_0RjKAnTK2AhN83DjhgLZnacV5lZPCH39lif-9Q9svBzsw7qw-k/s1600/centos7_www.hackthesec.co.in.png" /></a></div>
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<div style="color: #333333; font-family: verdana, geneva, sans-serif;">
<ul style="font-size: 15px; line-height: 26px; text-align: left;">
<li>GNOME</li>
<li> KDE</li>
<li> Unity (For <a href="http://www.hackthesec.co.in/search/label/Ubuntu">Ubuntu</a>)</li>
<li> Cinnamon (For of GNOME, originally developed by Linux Mint)</li>
<li>LXDE</li>
</ul>
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<span style="font-size: 15px; line-height: 26px;">In this post, we will install GNOME desktop on <a href="http://www.hackthesec.co.in/search/label/Centos">CentOS 7</a> which is popular and widely used. You can opt for other Desktop Environment alternative.</span></div>
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<span style="font-size: 15px; line-height: 26px;"><b><u><span style="color: #0b5394;">Steps To Install GNOME Desktop on CentOS 7</span></u></b></span></div>
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<span style="font-size: 15px; line-height: 26px;">1. Login as Root on CentOS 7 system or switch to super user after login</span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 19.2px; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white;"><span style="line-height: 20.8px;"><span style="font-size: large;">sudo su -</span></span></span></pre>
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<span style="color: #333333;"><span style="font-size: 15px; line-height: 26px;">2. Take the backup of data which you want to save. (Make a habit of taking backup, it is a good practice)</span></span></div>
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<span style="color: #333333;"><span style="font-size: 15px; line-height: 26px;">3. Run the command –</span></span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">yum groupinstall "GNOME Desktop"</span></span></pre>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">NOTE: Installing Desktop will consume time. When we installed the GNOME Desktop, all packages size was aggregated to more than 700 MB. This was the case for minimal installed CentOS 7. We recommend to install Desktop when your system have good internet speed.</span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><br /></span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">4. This is not an end yet. To get the Desktop on every system boot, run the given below command.</span></span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">systemctl set-default graphical.target</span></span></pre>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">5. Restart the CentOS 7 system.</span></span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">init 6</span></span></pre>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">6. On system reboot, you will get some questions on screen to answer. These are as follows –</span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">(a) EULA</span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Accept the license.</span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">(b) Language Setting</span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Select your language</span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">(c) Keyboard Typing</span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Select your keyboard type</span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">(d) Timezone</span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Select your country time zone.</span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">(e) User Creation</span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Create your user and set the password</span></span></div>
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<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">(f) "You're All Set"</span></span></div>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">You will get the finishing line as written just above.</span></span></div>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">You are all set now. You can start working on your desktop. Restart the system and check it once again.</span></span></div>
</div>
<div>
<div style="font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">
<b><u><span style="color: #0b5394;">Do you know that</span></u></b></div>
<div style="color: #333333; font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">
(A)Once the installation of "GNOME Desktop" is completed. You can get into Desktop from your black terminal. For this you have to run the command –</div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">startx</span></span></pre>
</div>
</div>
<div>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">(B)</span></span><span style="color: #333333; font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">Start the graphical.target service to directly switch to Desktop without reboot</span></div>
</div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">systemctl start graphical.target</span></span></pre>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white;"><span style="line-height: 20.8px;"><a href="http://www.hackthesec.co.in/">www.hackthesec.co.in</a></span></span></pre>
</div>
</div>
</div>

How Install Desktop on CentOS 7

Install Desktop on CentOS Now in this post, we will show how to install Desktop on CentOS 7. As a linux user , you should be aware tha...

How to Monitor Linux Memory Bandwidth

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<h1 class="eb-entry-title reset-heading  " id="title-1742" itemprop="name headline" style="font-family: 'Open Sans'; line-height: 50px; margin: 0px 0px 20px; text-rendering: optimizeLegibility;">
<span style="color: #990000; font-size: large;"><u>Monitor Linux Memory Bandwidth</u></span></h1>
<div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4a8iZO_zrZ60HfkE5rSQoGSI90nSlLKqUNjWqNIc_g5RANjhp143nZ-fJXB-DQyTytp7ddhRe3ssfCldV7PqyJxoFYKh6-AitW7K7J9BRJ-ZBo2DWy8oC0cXRXI978qt0c_GzYCWOB7_y/s1600/memory_test_www.hackthesec.co.in.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4a8iZO_zrZ60HfkE5rSQoGSI90nSlLKqUNjWqNIc_g5RANjhp143nZ-fJXB-DQyTytp7ddhRe3ssfCldV7PqyJxoFYKh6-AitW7K7J9BRJ-ZBo2DWy8oC0cXRXI978qt0c_GzYCWOB7_y/s1600/memory_test_www.hackthesec.co.in.jpg" /></a></div>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><b><br /></b></span></span></div>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><b>Requirements</b></span></span></div>
<div>
<ul style="text-align: left;">
<li><span style="color: #333333; font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">glibc 2.14 / Intel</span></li>
<li><span style="color: #333333; font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">nasm - General-purpose x86 assembler</span></li>
</ul>
</div>
<div>
<span style="color: #0b5394; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><b><u>Installing Memory Bandwidth</u></b></span></span></div>
</div>
<div>
<div style="font-family: verdana, geneva, sans-serif;">
<span style="font-size: 15px; line-height: 26px;">Download The Package From <a href="https://www.mediafire.com/?yenef2319acep6p">Here</a></span></div>
<div style="font-family: verdana, geneva, sans-serif;">
<u>https://www.mediafire.com/?yenef2319acep6p</u></div>
<div style="font-family: verdana, geneva, sans-serif;">
<u><br /></u></div>
<div style="font-family: verdana, geneva, sans-serif;">
<u><br /></u></div>
<div>
<div style="font-family: verdana, geneva, sans-serif;">
<b><u><span style="color: #0b5394;">Install Requirement nasm</span></u></b></div>
<div style="font-family: verdana, geneva, sans-serif;">
<b><u><span style="color: #0b5394;"><br /></span></u></b></div>
<div style="font-family: verdana, geneva, sans-serif;">
<b> RedHat</b></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;"># yum -y install nasm</span></span></pre>
</div>
<div style="font-family: verdana, geneva, sans-serif;">
<b>Debian </b></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;"># apt-get install nasm</span></span></pre>
</div>
<div style="font-family: verdana, geneva, sans-serif;">
<b>Gentoo </b></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;"># emerge nasm</span></span></pre>
</div>
<div style="font-family: verdana, geneva, sans-serif;">
<b>Arch Linux </b></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;"># pacman -S nasm</span></span></pre>
</div>
<div style="font-family: verdana, geneva, sans-serif;">
<b>FreeBSD</b></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;"># pkg install nasm</span></span></pre>
</div>
<div>
<div>
<span style="font-family: verdana, geneva, sans-serif;">Now unzip it</span></div>
<div>
<br /></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;"># tar zxvf bandwidth-1.2.0.tar.gz
# cd bandwidth-1.2.0</span></span></pre>
</div>
<div>
<span style="font-family: verdana, geneva, sans-serif;">Now we can create the executable by typing:</span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;"># make bandwidth64</span></span></pre>
</div>
<div>
<div>
<span style="font-family: verdana, geneva, sans-serif;">Commands available for compiling</span><span style="font-family: verdana, geneva, sans-serif;"> </span></div>
<div>
<span style="font-family: verdana, geneva, sans-serif;"><br /></span></div>
<div>
<span style="font-family: verdana, geneva, sans-serif;">To compile for x86 Linux: make bandwidth32</span></div>
<div>
<span style="font-family: verdana, geneva, sans-serif;">To compile for x86_64 Linux: make bandwidth64</span></div>
<div>
<span style="font-family: verdana, geneva, sans-serif;">To compile for x86 Mac OS/X: make bandwidth-mac32</span></div>
<div>
<span style="font-family: verdana, geneva, sans-serif;">To compile for x86_64 Mac OS/X: make bandwidth-mac64</span></div>
<div>
<span style="font-family: verdana, geneva, sans-serif;">To compile for ARM Linux: make bandwidth-arm32</span></div>
<div>
<span style="font-family: verdana, geneva, sans-serif;">To compile for x86 Win32/Cygwin: make bandwidth-win32</span></div>
<div>
<span style="font-family: verdana, geneva, sans-serif;">Note: For the Mac you will need to install the latest NASM; Apple's is insufficient.</span></div>
<div>
<span style="font-family: verdana, geneva, sans-serif;"><br /></span></div>
<div>
<span style="font-family: verdana, geneva, sans-serif;">Successful! Now let's run bandwidth64</span></div>
</div>
</div>
</div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;"># ./bandwidth64</span></span></pre>
</div>
<div>
<span style="font-family: verdana, geneva, sans-serif;">Output</span></div>
<div>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;"><span style="color: #333333; font-family: Menlo, Monaco, Consolas, Courier New, monospace;"><span style="font-size: 12px; line-height: 18.5714px;">This is bandwidth version 1.1.

Copyright (C) 2005-2015 by Zack T Smith.
This software is covered by the GNU Public License.
It is provided AS-IS, use at your own risk.
See the file COPYING for more information.

CPU family: GenuineIntel
CPU features: MMX SSE SSE2 SSE3 SSSE3 SSE4.1 SSE4.2 AES XD Intel64

Cache 0: L1 data cache, line size 64, 8-ways, 64 sets, size 32k
Cache 1: L1 instruction cache, line size 64, 4-ways, 128 sets, size 32k
Cache 2: L2 unified cache, line size 64, 8-ways, 512 sets, size 256k
Cache 3: L3 unified cache, line size 64, 16-ways, 12288 sets, size 12288k

Notation: B = byte, kB = 1024 B, MB = 1048576 B.

CPU speed is 3458.2 MHz.

Sequential read (128-bit), size = 128 B, loops = 2114977792, 51635.0 MB/s
Sequential read (128-bit), size = 256 B, loops = 1162084352, 56740.6 MB/s
Sequential read (128-bit), size = 384 B, loops = 774719946, 56736.7 MB/s
Sequential read (128-bit), size = 512 B, loops = 581042176, 56739.8 MB/s
Sequential read (128-bit), size = 640 B, loops = 464831081, 56735.2 MB/s
Sequential read (128-bit), size = 768 B, loops = 387359973, 56734.4 MB/s
Sequential read (128-bit), size = 896 B, loops = 332022834, 56738.5 MB/s
Sequential read (128-bit), size = 1024 B, loops = 290586624, 56743.8 MB/s
Sequential read (128-bit), size = 1280 B, loops = 232413324, 56740.8 MB/s
Sequential read (128-bit), size = 2 kB, loops = 145260544, 56737.8 MB/s
Sequential read (128-bit), size = 3 kB, loops = 96838885, 56736.9 MB/s
Sequential read (128-bit), size = 4 kB, loops = 72630272, 56742.0 MB/s
Sequential read (128-bit), size = 6 kB, loops = 48417226, 56738.5 MB/s
Sequential read (128-bit), size = 8 kB, loops = 36315136, 56740.0 MB/s
Sequential read (128-bit), size = 12 kB, loops = 24214074, 56741.2 MB/s
Sequential read (128-bit), size = 16 kB, loops = 18157568, 56735.7 MB/s
Sequential read (128-bit), size = 20 kB, loops = 14525784, 56740.4 MB/s
Sequential read (128-bit), size = 24 kB, loops = 12104820, 56735.9 MB/s
Sequential read (128-bit), size = 28 kB, loops = 10375560, 56738.7 MB/s
Sequential read (128-bit), size = 32 kB, loops = 8742912, 54640.6 MB/s
Sequential read (128-bit), size = 34 kB, loops = 6781113, 45025.7 MB/s
Sequential read (128-bit), size = 36 kB, loops = 5341700, 37553.3 MB/s
Sequential read (128-bit), size = 40 kB, loops = 4810806, 37580.8 MB/s
Sequential read (128-bit), size = 48 kB, loops = 4013100, 37622.4 MB/s
Sequential read (128-bit), size = 64 kB, loops = 3014656, 37673.6 MB/s</span></span></pre>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;"><span style="color: #333333; font-family: Menlo, Monaco, Consolas, Courier New, monospace;"><span style="font-size: 12px; line-height: 18.5714px;"><a href="http://www.hackthesec.co.in/">www.hackthesec.co.in</a></span></span></pre>
</div>
</div>
</div>

How to Monitor Linux Memory Bandwidth

Monitor Linux Memory Bandwidth Requirements glibc 2.14 / Intel nasm - General-purpose x86 assembler Installing Memory Bandw...

Reverse SSH Tunneling

<div dir="ltr" style="text-align: left;" trbidi="on">
<h1 style="box-sizing: border-box; font-family: Raleway, Helvetica, Arial, sans-serif; font-size: 33px; line-height: 46px; margin: 0px 0px 8px;">
<u><span style="color: #990000;">Reverse SSH Tunneling</span></u></h1>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">In this tutorial we will covering how to bypass these restrictions using a technique called Rerverse SSH Tunneling.</span></span></div>
<div>
<span style="color: red; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Note: This tutorial assumes you are using <a href="http://www.hackthesec.co.in/search/label/Ubuntu">Ubuntu</a>. The steps however are expected to work for other Linux distribution.</span></span></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3dFwWxIAlnnoDhDUBOag_ZQ0mYlSo6eEfDyfC6CSSbfYnV4vavMfV_dS1L6uUBQxUwyIVqx0i1e4LxGzT3iQcRrilQ_b4IjjV7pAxmi5soqSqVrL4KPZSCqWMH0ERC4mC2gXzXY2s6dFT/s1600/ssh-hackthesec.co.in.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3dFwWxIAlnnoDhDUBOag_ZQ0mYlSo6eEfDyfC6CSSbfYnV4vavMfV_dS1L6uUBQxUwyIVqx0i1e4LxGzT3iQcRrilQ_b4IjjV7pAxmi5soqSqVrL4KPZSCqWMH0ERC4mC2gXzXY2s6dFT/s1600/ssh-hackthesec.co.in.jpg" /></a></div>
<div>
<span style="color: red; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><br /></span></span></div>
<div>
<div style="font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">
<b><span style="color: #0b5394;"><u>Prerequisites:</u></span></b></div>
<div>
<ul style="font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px; text-align: left;">
<li>An Ubuntu server instance.</li>
<li>A SSH Client on your local machine.</li>
</ul>
<div>
<div style="font-family: verdana, geneva, sans-serif;">
<span style="font-size: 15px; line-height: 26px;"><b><u><span style="color: #0b5394;">Step 1: Configuring SSH daemon on your server:</span></u></b></span></div>
<div style="font-family: verdana, geneva, sans-serif;">
<span style="font-size: 15px; line-height: 26px;">By default, <a href="http://www.hackthesec.co.in/search/label/SSH">SSH </a>daemon is only listening on <span style="color: red;">127.0.0.1</span>, so we won’t be able to access to our forwarded ports from outside. To get it listen on the interface connected to Internet we must enable <span style="color: red;">GatewayPorts </span>option in <a href="http://www.hackthesec.co.in/search/label/SSH">SSH </a>server's configuration.</span></div>
<div style="font-family: verdana, geneva, sans-serif;">
<span style="font-size: 15px; line-height: 26px;"><br /></span></div>
<div style="font-family: verdana, geneva, sans-serif;">
<span style="font-size: 15px; line-height: 26px;">Open <b>/etc/ssh/sshd_config</b> using your favorite text editor.</span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">nano /etc/ssh/sshd_config</span></span></pre>
</div>
<div style="font-family: verdana, geneva, sans-serif;">
<span style="font-size: 15px; line-height: 26px;">Then add <b><span style="color: red;">GatewayPorts yes</span></b> at the bottom of the file.</span></div>
<div style="font-family: verdana, geneva, sans-serif;">
<span style="font-size: 15px; line-height: 26px;">After saving the file, restart the SSH daemon:</span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">service ssh restart</span></span></pre>
</div>
</div>
</div>
<div>
<div>
<span style="color: #0b5394; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><b><u>Step 2: Tunneling:</u></b></span></span></div>
<div>
<span style="font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">If your home computer runs Linux, you’ll need to use the ssh command as follows:</span></span></div>
</div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">ssh -R [Port to forward to on your VPS]:localhost:[Port to forward on your local machine] [VPS IP]</span></span></pre>
</div>
<div>
<span style="font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Or if you have installed Microsoft Windows on your machine then you have to install <a href="http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html">plink</a> and connect as shows below:</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">plink -R [Port to forward to on your VPS]:localhost:[Port to forward on your local machine] [VPS IP]</span></span></pre>
</div>
<div>
<span style="font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">In this example, we’re forwarding port <b>19132</b> which is open on your at-home machine to port <b>80 </b>on your remote server (assuming your server's IP Address is <b>192.168.0.1</b>).</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">ssh -R 80:localhost:19132 192.168.0.1</span></span></pre>
</div>
<div>
<span style="font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">This will allow you to access your at-home machine from a remote location by connecting to <b>192.168.0.1:80</b></span></span></div>
<div style="font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">
<a href="http://www.hackthesec.co.in/">www.hackthesec.co.in</a></div>
</div>
</div>

Reverse SSH Tunneling

Reverse SSH Tunneling In this tutorial we will covering how to bypass these restrictions using a technique called Rerverse SSH Tunneling...

Setup SFTP-only User Accounts on CentOS 7

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<h1 style="box-sizing: border-box; font-family: Raleway, Helvetica, Arial, sans-serif; line-height: 46px; margin: 0px 0px 8px;">
<span style="color: #990000; font-size: large;"><u>Setup SFTP-only User Accounts on CentOS</u></span></h1>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">The SSH File Transfer Protocol (also Secure File Transfer Protocol, or SFTP) is a network protocol that provides file access, file transfer, and file management over any reliable data stream. It was designed by the Internet Engineering Task Force (IETF) as an extension of the Secure Shell protocol (<a href="http://www.hackthesec.co.in/search/label/SSH">SSH</a>) version 2.0 to provide secure file </span></span></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0UoU738wfzIiGQcNwEh7rGJzNHBJmmJiBCvuVQpMOAdQltLab9w4pAzEuFpSuexA7trPxiLLFCLlTR2TJ-Iuw-Tz4zF2QdvvYDZr5vwxR2dW0WcSbp6qnjOAC6quoc-tRpzxf6KI3tkgX/s1600/sftp-software-hackthesec.co.in.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0UoU738wfzIiGQcNwEh7rGJzNHBJmmJiBCvuVQpMOAdQltLab9w4pAzEuFpSuexA7trPxiLLFCLlTR2TJ-Iuw-Tz4zF2QdvvYDZr5vwxR2dW0WcSbp6qnjOAC6quoc-tRpzxf6KI3tkgX/s1600/sftp-software-hackthesec.co.in.jpg" /></a></div>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><br /></span></span></div>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">transfer capabilities. The IETF Internet Draft states that, even though this protocol is described in the context of the SSH-2 protocol, it could be used in a number of different applications, such as secure file transfer over Transport Layer Security (TLS) and transfer of management information in <a href="http://www.hackthesec.co.in/search/label/VPN">VPN </a>applications.</span></span></div>
<div>
<span style="color: #0b5394; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><b><u>Step 1: Create a dedicated sFTP group and a dedicated sFTP user</u></b></span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-size: large;"><span style="line-height: 20.8px;"><span style="color: white;">groupadd sftpusers
</span><span style="color: orange;">useradd -G sftpusers -s /sbin/nologin user1
</span><span style="color: white;">passwd user1</span></span></span></pre>
</div>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Here, the group <b>sftpusers </b>is a dedicated sFTP group, the user <b>user1 </b>is a dedicated sFTP user which is forbidden to log in using SSH.</span></span></div>
<div>
<span style="color: #0b5394; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><b><u>Step 2: Modify the configuration of the sshd service</u></b></span></span></div>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Open the configuration file of the sshd service:</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: large;"><span style="line-height: 20.8px;">vi /etc/ssh/sshd_config</span></span></pre>
</div>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Find the line:</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: orange; font-size: large;"><span style="line-height: 20.8px;">Subsystem sftp /usr/libexec/openssh/sftp-server</span></span></pre>
</div>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Replace it with:</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-size: large;"><span style="line-height: 20.8px;"><span style="color: white;">Subsystem </span><span style="color: orange;">sftp internal-sftp</span></span></span></pre>
</div>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Append the following lines to the end of the file. The group name <b>sftpusers </b>should be the same as the one you specified earlier.</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-size: large;"><span style="line-height: 20.8px;"><span style="color: white;">Match Group sftpusers
X11Forwarding no
AllowTcpForwarding no
</span><span style="color: orange;">ChrootDirectory %h
</span><span style="color: white;">ForceCommand internal-sftp</span></span></span></pre>
</div>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Save and quit: use :wq</span></span></div>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Restart the sshd service to put your changes into effect.</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-size: large;"><span style="line-height: 20.8px;"><span style="color: white;">systemctl </span><span style="color: orange;">restart sshd.service</span></span></span></pre>
</div>
<div>
<div style="font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">
<b><u><span style="color: #0b5394;">Step 3: Create a dedicated directory for the sFTP-only user</span></u></b></div>
<div style="color: #333333; font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">
You need to specify a directory for the sFTP-only user and make sure that this user can only play around in this directory:</div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-size: large;"><span style="line-height: 20.8px;"><span style="color: white;">chown -R root /home/user1
chmod -R 755 /home/user1
</span><span style="color: orange;">mkdir /home/user1/files
</span><span style="color: white;">chown user1. /home/user1/files</span></span></span></pre>
</div>
</div>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Now, the user <b>user1 </b>can only upload and/or download files in the directory <b>/home/user1/files</b>, he or she can never touch other users' files.</span></span></div>
<div>
<span style="font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><div>
<b><u><span style="color: #0b5394;">Step 4: Create more sFTP-only users</span></u></b></div>
<div style="color: #333333;">
If you need more sFTP-only users, you can create them in the same fashion:</div>
</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-size: large;"><span style="line-height: 20.8px;"><span style="color: orange;">useradd -G sftpusers -s /sbin/nologin user2
passwd user2</span><span style="color: white;">
chown -R root /home/user2
chmod -R 755 /home/user2
mkdir /home/user2/files
chown user2. /home/user2/files</span></span></span></pre>
</div>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">That's it. Each user account created in this fashion will be denied if you use it to log in the system. These user accounts can be used only in sFTP programs.</span></span></div>
<div>
<span style="color: #333333; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><a href="http://www.hackthesec.co.in/">www.hackthesec.co.in</a></span></span></div>
</div>

Setup SFTP-only User Accounts on CentOS 7

Setup SFTP-only User Accounts on CentOS The SSH File Transfer Protocol (also Secure File Transfer Protocol, or SFTP) is a network protoc...

How to install squid proxy on centos

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<h1 style="clear: both; font-family: Trebuchet, 'Trebuchet MS', Arial, Verdana, sans-serif; font-size: 30px; height: auto; line-height: 31px; margin: 0px; padding: 0px; width: 614px;">
<u><span style="color: #990000;">Install squid proxy on centos</span></u></h1>
<div>
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">Squid is a caching and forwarding web proxy. It has a wide variety of uses, from speeding up a web server by caching repeated requests; to caching web, <a href="http://www.hackthesec.co.in/search/label/DNS">DNS</a> and other computer network lookups for a group of people sharing network resources; to aiding security by filtering traffic. Although primarily used for HTTP and <a href="http://www.hackthesec.co.in/search/label/ftp">FTP</a>, Squid includes limited support for several other protocols including TLS, SSL, Internet Gopher and HTTPS</span></span><span style="background-color: white; color: #333333; font-family: "verdana" , "geneva" , sans-serif; font-size: 15px; line-height: 26px;">.</span></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtuLbkofJ_zaadojyg-kg2TTym3Z1SblRiTiwNCaRRxvNfwE7UGzMyriv33EkqCKKK-PNDNIrXMTxl633f8uUdiToe_67H4UK77mB5VOLK7hTbxGaSICl3pNA6navN1-2mqAmMYhmcMrOT/s1600/squid_www.hackthesec.co.in.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtuLbkofJ_zaadojyg-kg2TTym3Z1SblRiTiwNCaRRxvNfwE7UGzMyriv33EkqCKKK-PNDNIrXMTxl633f8uUdiToe_67H4UK77mB5VOLK7hTbxGaSICl3pNA6navN1-2mqAmMYhmcMrOT/s1600/squid_www.hackthesec.co.in.png" /></a></div>
<div>
<span style="background-color: white; color: #333333; font-family: "verdana" , "geneva" , sans-serif; font-size: 15px; line-height: 26px;"><br /></span></div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">Update yum repositories and packages by typing the below command</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;">[root@hackthesec ~]# yum update</span></span></pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">Step 1:- Install squid package and dependencies using the below command</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;">[root@hackthesec ~]# yum install squid</span></span></pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">By default squid configuration file "<b>/etc/squid/squid.conf</b>" will contains recommended minimum configuration  and squid caching feature will work without making any changes . Recommended minimum configuration will looks like the below</span></span></div>
<div>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 13px; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;">#
# Recommended minimum configuration:
#
acl manager proto cache_object
acl localhost src 127.0.0.1/32 ::1
acl to_localhost dst 127.0.0.0/8 0.0.0.0/32 ::1

# Example rule allowing access from your local networks.
# Adapt to list your (internal) IP networks from where browsing
# should be allowed
acl localnet src 10.0.0.0/8     # RFC1918 possible internal network
acl localnet src 172.16.0.0/12  # RFC1918 possible internal network
acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
acl localnet src fc00::/7       # RFC 4193 local private network range
acl localnet src fe80::/10      # RFC 4291 link-local (directly plugged) machines

acl SSL_ports port 443
acl Safe_ports port 80          # http
acl Safe_ports port 21          # ftp
acl Safe_ports port 443         # https
acl Safe_ports port 70          # gopher
acl Safe_ports port 210         # wais
acl Safe_ports port 1025-65535  # unregistered ports
acl Safe_ports port 280         # http-mgmt
acl Safe_ports port 488         # gss-http
acl Safe_ports port 591         # filemaker
acl Safe_ports port 777         # multiling http
acl CONNECT method CONNECT

#
# Recommended minimum Access Permission configuration:
#
# Only allow cachemgr access from localhost
http_access allow manager localhost
http_access deny manager

# Deny requests to certain unsafe ports
http_access deny !Safe_ports

# Deny CONNECT to other than secure SSL ports
http_access deny CONNECT !SSL_ports

# We strongly recommend the following be uncommented to protect innocent
# web applications running on the proxy server who think the only
# one who can access services on "localhost" is a local user
#http_access deny to_localhost

#
# INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
#
# Example rule allowing access from your local networks.
# Adapt localnet in the ACL section to list your (internal) IP networks
# from where browsing should be allowed
http_access allow localnet
http_access allow localhost

# And finally deny all other access to this proxy
http_access deny all

# Squid normally listens to port 3128
http_port 3128

# We recommend you to use at least the following line.
hierarchy_stoplist cgi-bin ?

# Uncomment and adjust the following to add a disk cache directory.
#cache_dir ufs /var/spool/squid 100 16 256

# Leave coredumps in the first cache dir
coredump_dir /var/spool/squid

# Add any of your own refresh_pattern entries above these.
refresh_pattern ^ftp:           1440    20%     10080
refresh_pattern ^gopher:        1440    0%      1440
refresh_pattern -i (/cgi-bin/|?) 0     0%      0
refresh_pattern .               0       20%     4320</pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">Step 2:- Now start squid service</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;">[root@hackthesec ~]# service squid start</span></span></pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">and type this below command to start squid service automatically while booting.</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;">[root@hackthesec ~]# chkconfig --levels 235 squid on</span></span></pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"></span></span><br />
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">Step 3:- Setup your web browser to access Internet through proxy server on port 3128</span></span></div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">
<div>
<br /></div>
<div>
IE : Tools » Internet options »Connections » LAN settings » Choose "Use a proxy server for your LAN" » Type your Proxy server ip (192.168.1.11 ) and port no 3128</div>
<div>
<br /></div>
<div>
Firefox : Options / Preferences » Advanced » Network » Settings » Choose "Manual proxy configuration " » Type your Proxy server ip (192.168.1.11 ) and port no 3128</div>
<div>
<br /></div>
<div>
Step 4:- Browse some sites and check the access log file on proxy server</div>
</span></span></div>
<div>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 13px; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;">[root@hackthesec ~]# cat /var/log/squid/access.log
1343759484.645    265 192.168.1.15 TCP_MISS/304 477 GET http://platform.twitter.com/widgets.js - DIRECT/23.64.79.144 application/javascript
1343759484.681    309 192.168.1.15 TCP_MISS/304 839 GET http://apis.google.com/js/plusone.js - DIRECT/173.194.36.36 -
1343759485.005    178 192.168.1.15 TCP_MISS/200 495 GET http://www.google-analytics.com/__utm.gif? - DIRECT/74.125.236.142 image/gif
1343759502.763  20292 192.168.1.15 TCP_MISS/200 1898 CONNECT s-static.ak.facebook.com:443 - DIRECT/23.64.66.110 -
1343759502.765  20292 192.168.1.15 TCP_MISS/200 1898 CONNECT s-static.ak.facebook.com:443 - DIRECT/23.64.66.110 -
1343759723.040 240567 192.168.1.15 TCP_MISS/200 2904 CONNECT plusone.google.com:443 - DIRECT/173.194.36.41 -
1343759934.518    459 192.168.1.15 TCP_MISS/200 495 GET http://www.google-analytics.com/__utm.gif? - DIRECT/173.194.36.8 image/gif
1343759943.131   2186 192.168.1.15 TCP_MISS/200 8343 CONNECT www.facebook.com:443 - DIRECT/66.220.146.94 -
1343759943.266  10616 192.168.1.15 TCP_MISS/200 2790 CONNECT apis.google.com:443 - DIRECT/74.125.236.128 -
1343759943.267  10615 192.168.1.15 TCP_MISS/200 2228 CONNECT ssl.gstatic.com:443 - DIRECT/74.125.236.143 -
1343759950.875   2596 192.168.1.15 TCP_MISS/200 32219 CONNECT www.facebook.com:443 - DIRECT/66.220.146.94 -
1343759961.388  20443 192.168.1.15 TCP_MISS/200 1911 CONNECT s-static.ak.fbcdn.net:443 - DIRECT/23.64.77.177 -</pre>
</div>
<div>
<span style="background-color: white;"></span><br />
<div style="font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">
<span style="background-color: white;"><b><u><span style="color: #0b5394;">Troubleshooting :</span></u></b></span></div>
<span style="background-color: white;">
<div style="color: #333333; font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">
If you not able to browse using proxy settings , Disable the firewall ( iptables ) and selinux service on your squid proxy server .</div>
<div style="color: #333333; font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">
<b>Disable firewall ( Iptables ) :-</b></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;">[root@hackthesec ~]# service iptables stop
[root@hackthesec ~]# chkconfig iptables off</span></span></pre>
</div>
</span></div>
<div>
<span style="background-color: white;"></span><br />
<div>
<span style="background-color: white;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">Disable Selinux :- open the file /etc/selinux/config and find the line</span></span></span></div>
<span style="background-color: white;">
</span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;">SELINUX=enforcing</span></span></pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">and replace with</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;">SELINUX=disabled</span></span></pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">now reboot the server and try step 4.</span></span></div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="font-family: "verdana" , "geneva" , sans-serif;"></span></span><br />
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="font-family: "verdana" , "geneva" , sans-serif;"><b><span style="color: #0b5394;"><u>Configure squid proxy as web filter:</u></span></b></span></span></div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="font-family: "verdana" , "geneva" , sans-serif;">
<div style="color: #333333;">
You can restrict user access to particular websites or keywords using access control lists (ACLs) .</div>
<div>
<b><span style="color: #0b5394;"><u>Restricting Access to specific web sites :</u></span></b></div>
<div style="color: #333333;">
For example , we can see how to block facebook.com and gmail.com .</div>
<div style="color: #333333;">
Step 1:- create a file ( <b>/etc/squid/blockedsites.squid</b> ) and add the site names one per line.</div>
</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;">[root@hackthesec ~]# cat /etc/squid/blockedsites.squid
#blocked sites
www.facebook.com
www.gmail.com</span></span></pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">Step 2:- Open the /etc/squid/squid.conf and create a new acl " blocksites" and acl type "dstdomain" in the acl section like the below .</span></span></div>
<div>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 13px; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;">acl Safe_ports port 488         # gss-http
acl Safe_ports port 591         # filemaker
acl Safe_ports port 777         # multiling http
acl CONNECT method CONNECT
# ACL blocksites 
acl blocksites dstdomain "/etc/squid/blockedsites.squid"</pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">and add the following line "<b>http_access deny blocksites</b>" to http_section to deny the access to the acl "<b>blocksites</b>" .</span></span></div>
<div>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 13px; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;"># Recommended minimum Access Permission configuration:
#
# Only allow cachemgr access from localhost
http_access allow manager localhost
# Deny access to blocksites ACL
http_access deny blocksites</pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">Step 3:- Now restart squid service</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;">[root@hackthesec ~]# service squid restart</span></span></pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">Step 4:- Try to access facebook.com in your browser . you could see the blocked page as below .</span></span></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitsQRp6xcr5AmcJgrWIHEyVE274ObQfkcEWpNTBGqT_25fkxX_ryBbASwHU-G3Iwsye8ZiK2CDfkIEo6AU3h-ZmCZtF4of10Dt34mqj-ryTojXljt7XEsIrjcl-LADcICkQ61A8Yl4cXKE/s1600/squid_proxy_server_block_www.hackthesec.co.in.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitsQRp6xcr5AmcJgrWIHEyVE274ObQfkcEWpNTBGqT_25fkxX_ryBbASwHU-G3Iwsye8ZiK2CDfkIEo6AU3h-ZmCZtF4of10Dt34mqj-ryTojXljt7XEsIrjcl-LADcICkQ61A8Yl4cXKE/s1600/squid_proxy_server_block_www.hackthesec.co.in.jpg" /></a></div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><br /></span></span></div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">and check the log file you can see the facebook request is denied .</span></span></div>
<div>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 13px; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;"> [root@hackthesec ~]# tail -f /var/log/squid/access.log
.................................................................................
1343820985.542      1 192.168.1.15 TCP_DENIED/403 4255 GET http://www.facebook.com/ - NONE/- text/html
1343820986.998   1411 192.168.1.15 TCP_MISS/200 13152 GET http://www.squid-cache.org/Artwork/SN.png - DIRECT/198.186.193.234 image/png
1343820987.004      0 192.168.1.15 TCP_DENIED/403 4178 GET http://www.facebook.com/favicon.ico - NONE/- text/html</pre>
</div>
<div>
<span style="background-color: white;"></span><br />
<div style="font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">
<span style="background-color: white;"><b><u><span style="color: #0b5394;">Restricting Access to specific keywords :</span></u></b></span></div>
<span style="background-color: white;">
<div style="color: #333333; font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">
Step 1:- create a file (<b> /etc/squid/blockkeywords.squid</b> ) and add the keywords one per line.</div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;">[root@hackthesec ~]# cat /etc/squid/blockkeywords.squid
#blocked keywords
sex
porn
xxx</span></span></pre>
</div>
</span></div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">Step 2:- Open the <b>/etc/squid/squid.conf</b> and create a new acl "blockkeywords" and acl type "url_regex" in the acl section</span></span></div>
<div>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 13px; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;">acl Safe_ports port 488         # gss-http
acl Safe_ports port 591         # filemaker
acl Safe_ports port 777         # multiling http
acl CONNECT method CONNECT
# ACL blocksites 
acl blocksites dstdomain "/etc/squid/blockedsites.squid"
# ACL blockkeywords
acl blockkeywords url_regex -i "/etc/squid/blockkeywords.squid"</pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">and add the following line "http_access deny blockkeywords" to http_section to deny the access to the acl "<b>blockkeywords</b>" .</span></span></div>
<div>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 13px; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;"># Recommended minimum Access Permission configuration:
#
# Only allow cachemgr access from localhost
http_access allow manager localhost
# Deny access to blocksites ACL
http_access deny blocksites
# Deny access to blockkeywords ACL
http_access deny blockkeywords</pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="font-family: "verdana" , "geneva" , sans-serif;"></span></span><br />
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="font-family: "verdana" , "geneva" , sans-serif;"><b><span style="color: #0b5394;"><u>Restricting Access to specific Ipaddress :</u></span></b></span></span></div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="font-family: "verdana" , "geneva" , sans-serif;">
<div style="color: #333333;">
Step 1:- create a file ( /etc/squid/blockip.squid ) and add the ip adresses one per line.</div>
</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;">[root@hackthesec ~]# cat /etc/squid/blockip.squid
#blocked ips
192.168.1.20
192.168.1.21</span></span></pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">Step 2:- Open the /etc/squid/squid.conf and create a new acl "blockip" and acl type "src" in the acl section</span></span></div>
<div>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 13px; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;">acl Safe_ports port 488         # gss-http
acl Safe_ports port 591         # filemaker
acl Safe_ports port 777         # multiling http
acl CONNECT method CONNECT
# ACL blocksites 
acl blocksites dstdomain "/etc/squid/blockedsites.squid"
# ACL blockkeywords
acl blockkeywords url_regex -i "/etc/squid/blockkeywords.squid"
# ACL blockip
acl blockip src "/etc/squid/blockip.squid"</pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">and add the following line "http_access deny blockip" to http_section to deny the access to the acl "blockip" .</span></span></div>
<div>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 13px; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;"># Recommended minimum Access Permission configuration:
#
# Only allow cachemgr access from localhost
http_access allow manager localhost
# Deny access to blockip ACL
http_access deny blockip
# Deny access to blocksites ACL
http_access deny blocksites
# Deny access to blockkeywords ACL
http_access deny blockkeywords</pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="font-family: "verdana" , "geneva" , sans-serif;"></span></span><br />
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="font-family: "verdana" , "geneva" , sans-serif;"><b><u><span style="color: #0b5394;">Allow Full access to specific Ipaddress :</span></u></b></span></span></div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="font-family: "verdana" , "geneva" , sans-serif;">
<div style="color: #333333;">
You can allow specific ip address to gain full access without blocking sites and keywords . just create a file "/etc/squid/allowip.squid" and add the ip address one per line and create an acl "allowip"  and acl type "src" in the acl section</div>
</span></span></div>
<div>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 13px; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;"># ACL allowip
acl allowip src "/etc/squid/allowip.squid"</pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">and add the "allowip" in the http_access as below</span></span></div>
<div>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 13px; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;"># Recommended minimum Access Permission configuration:
#
# Only allow cachemgr access from localhost
http_access allow manager localhost
# Deny access to blockip ACL
http_access deny blockip
# Deny access to blocksites ACL
http_access deny blocksites !allowip
# Deny access to blockkeywords ACL
http_access deny blockkeywords !allowip</pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="font-family: "verdana" , "geneva" , sans-serif;"></span></span><br />
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="font-family: "verdana" , "geneva" , sans-serif;"><b><u><span style="color: #0b5394;">Changing squid proxy port number:</span></u></b></span></span></div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="font-family: "verdana" , "geneva" , sans-serif;">
<div style="color: #333333;">
You can change squid proxy port number , by default it uses 3128 port .</div>
<div style="color: #333333;">
Just find the below line in "/etc/squid/squid.conf"</div>
</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;">http_port 3128</span></span></pre>
</div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">and replace with</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;">http_port 8000 # whatever port number you want</span></span></pre>
</div>
<div>
<span style="background-color: white;"></span><br />
<div style="font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">
<span style="background-color: white;"><b><u><span style="color: #0b5394;">Restricting Download size :</span></u></b></span></div>
<span style="background-color: white;">
<div style="color: #333333; font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">
You can restrict download file size  using reply_body_max_size .</div>
<div style="color: #333333; font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">
Add the below line at the bottom of the http_access section</div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;">#Restrict download size
reply_body_max_size 10 MB all</span></span></pre>
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</span></div>
<div>
<span style="background-color: white; color: #333333; font-family: "verdana" , "geneva" , sans-serif; font-size: 15px; line-height: 26px;">or</span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;">#Restrict download size
reply_body_max_size 10 MB !allowip</span></span></pre>
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<div>
<span style="background-color: white;"></span><br />
<div style="font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">
<span style="background-color: white;"><b><u><span style="color: #0b5394;">Configuring Squid as Transparent Proxy :</span></u></b></span></div>
<span style="background-color: white;">
<div style="color: #333333; font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">
You can configure squid as transparent proxy .</div>
<div style="color: #333333; font-family: verdana, geneva, sans-serif; font-size: 15px; line-height: 26px;">
Step 1:- just find the below line</div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;"># Squid normally listens to port 3128
http_port 3128</span></span></pre>
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</span></div>
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">and replace with</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;"># Squid normally listens to port 3128
http_port 3128 intercept</span></span></pre>
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<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">Step 2:- Create a file "/root/squidfw.sh" and add the following firewall script ( modify as per your interface configuration ).</span></span></div>
<div>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 13px; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;">#!/bin/sh
# squid server IP
SQUID_SERVER="192.168.1.11"
# Interface connected to Internet
INTERNET="eth0"
# Interface connected to LAN
LAN_IN="eth1"
# Squid port
SQUID_PORT="3128"
# DO NOT MODIFY BELOW
# Clean old firewall
iptables -F
iptables -X
iptables -t nat -F
iptables -t nat -X
iptables -t mangle -F
iptables -t mangle -X
# Load IPTABLES modules for NAT and IP conntrack support
modprobe ip_conntrack
modprobe ip_conntrack_ftp
# For win xp ftp client
#modprobe ip_nat_ftp
echo 1 > /proc/sys/net/ipv4/ip_forward
# Setting default filter policy
iptables -P INPUT DROP
iptables -P OUTPUT ACCEPT
# Unlimited access to loop back
iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT
# Allow UDP, DNS and Passive FTP
iptables -A INPUT -i $INTERNET -m state --state ESTABLISHED,RELATED -j ACCEPT
# set this system as a router for Rest of LAN
iptables --table nat --append POSTROUTING --out-interface $INTERNET -j MASQUERADE
iptables --append FORWARD --in-interface $LAN_IN -j ACCEPT
# unlimited access to LAN
iptables -A INPUT -i $LAN_IN -j ACCEPT
iptables -A OUTPUT -o $LAN_IN -j ACCEPT
# DNAT port 80 request comming from LAN systems to squid 3128 ($SQUID_PORT) aka transparent proxy
iptables -t nat -A PREROUTING -i $LAN_IN -p tcp --dport 80 -j DNAT --to $SQUID_SERVER:$SQUID_PORT
# if it is same system
iptables -t nat -A PREROUTING -i $INTERNET -p tcp --dport 80 -j REDIRECT --to-port $SQUID_PORT
# DROP everything and Log it
iptables -A INPUT -j LOG
iptables -A INPUT -j DROP</pre>
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<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">Step 3:- just run the script</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;">[root@hackthesec ~]# sh /root/squidfw.sh</span></span></pre>
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<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">and add the below line to "/etc/rc.local" to run the script during startup</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;">sh /root/squidfw.sh</span></span></pre>
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<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"></span></span><br />
<div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">Step 4 (Updated):- Change default gateway ip to squid server ip on the user machines </span></span></div>
<span style="background-color: white; font-size: 15px; line-height: 26px;"><span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;">
<div>
Now users can access Internet without setting proxy in the browser settings.</div>
</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium;"><span style="line-height: 20.8px;"><a href="http://www.hackthesec.co.in/">www.hackthesec.co.in</a></span></span></pre>
</div>
</div>

How to install squid proxy on centos

Install squid proxy on centos Squid is a caching and forwarding web proxy. It has a wide variety of uses, from speeding up a web server ...

Linux/x86_x64 - execve(/bin/sh) - 26 bytes

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Linux/x86_x64 - execve(/bin/sh) - 26 bytes</h1>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNGd2dSE36EwqPaCLsFMlVvPBw4MFsIMMFoNRrktPQPkfwZYRyGljUGP89grcSgWlXsib9j_gzMc5JUKhZw_ouL0R5u4bbHt5OClOwfj7BVXNKPpV37ZMjFfB6I7qdMUlHYIwaVk4gk010/s1600/linux-command_www.hackthesec.co.in.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNGd2dSE36EwqPaCLsFMlVvPBw4MFsIMMFoNRrktPQPkfwZYRyGljUGP89grcSgWlXsib9j_gzMc5JUKhZw_ouL0R5u4bbHt5OClOwfj7BVXNKPpV37ZMjFfB6I7qdMUlHYIwaVk4gk010/s1600/linux-command_www.hackthesec.co.in.jpg" /></a></div>
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<table class="exploit_list" style="background-color: rgb(239, 239, 239) !important; border-radius: 3px !important; border-spacing: 1px; border: 1px solid rgb(221, 221, 221) !important; box-sizing: border-box; color: #666666; font-family: 'Open Sans', sans-serif; font-size: 14px; line-height: 24px; margin-bottom: 10px; margin-top: 10px; padding: 1px !important; width: 564px;"><tbody style="box-sizing: border-box;">
<tr style="background-color: rgb(248, 248, 248) !important; box-sizing: border-box;"><td style="box-sizing: border-box; padding: 5px 10px;"></td><td style="box-sizing: border-box; padding: 5px 10px;"><br /></td><td style="box-sizing: border-box; padding: 5px 10px;"></td></tr>
<tr style="background-color: rgb(248, 248, 248) !important; box-sizing: border-box;"><td style="box-sizing: border-box; padding: 5px 10px;"><strong style="box-sizing: border-box;">Download Exploit:</strong> <a href="https://www.exploit-db.com/download/39617" style="background-color: transparent; box-sizing: border-box; color: #337ab7; outline: 0px; text-decoration: none; transition-duration: 0.3s; transition-property: background-color, box-shadow, border, color, opacity;"><span class="fa fa-file-code-o" style="-webkit-font-smoothing: antialiased; box-sizing: border-box; display: inline-block; font-family: FontAwesome; font-size: inherit; font-stretch: normal; line-height: 1; text-rendering: auto;"></span> Source</a></td><td style="box-sizing: border-box; padding: 5px 10px;"><strong style="box-sizing: border-box;">Author:</strong> Ajith Kp</td><td style="box-sizing: border-box; padding: 5px 10px;"></td></tr>
<tr style="background-color: rgb(248, 248, 248) !important; box-sizing: border-box;"><td style="box-sizing: border-box; padding: 5px 10px;"><br /><br /><br /><a href="http://www.hackthesec.co.in/">www.hackthesec.co.in</a></td><td colspan="2" style="box-sizing: border-box; padding: 5px 10px;"><br /></td></tr>
</tbody></table>
</div>
</div>

Linux/x86_x64 - execve(/bin/sh) - 26 bytes

Linux/x86_x64 - execve(/bin/sh) - 26 bytes Download Exploit: Source Author: Ajith Kp www.hackthesec.co.in

Linux/x86_x64 - execve(/bin/sh) - 25 bytes

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<h1 style="background-color: white; box-sizing: border-box; color: #555555; font-family: 'Noto Sans', sans-serif; font-size: 38px; font-stretch: normal; font-weight: 300; line-height: 1.4; margin: 0px; text-align: center;">
Linux/x86_x64 - execve(/bin/sh) - 25 bytes</h1>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNGd2dSE36EwqPaCLsFMlVvPBw4MFsIMMFoNRrktPQPkfwZYRyGljUGP89grcSgWlXsib9j_gzMc5JUKhZw_ouL0R5u4bbHt5OClOwfj7BVXNKPpV37ZMjFfB6I7qdMUlHYIwaVk4gk010/s1600/linux-command_www.hackthesec.co.in.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNGd2dSE36EwqPaCLsFMlVvPBw4MFsIMMFoNRrktPQPkfwZYRyGljUGP89grcSgWlXsib9j_gzMc5JUKhZw_ouL0R5u4bbHt5OClOwfj7BVXNKPpV37ZMjFfB6I7qdMUlHYIwaVk4gk010/s1600/linux-command_www.hackthesec.co.in.jpg" /></a></div>
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<div class="info" style="box-sizing: border-box; float: left;">
<table class="exploit_list" style="background-color: rgb(239, 239, 239) !important; border-radius: 3px !important; border-spacing: 1px; border: 1px solid rgb(221, 221, 221) !important; box-sizing: border-box; margin-bottom: 10px; margin-top: 10px; padding: 1px !important; width: 564px;"><tbody style="box-sizing: border-box;">
<tr style="background-color: rgb(248, 248, 248) !important; box-sizing: border-box;"><td style="box-sizing: border-box; padding: 5px 10px;"></td><td style="box-sizing: border-box; padding: 5px 10px;"><br /></td><td style="box-sizing: border-box; padding: 5px 10px;"></td></tr>
<tr style="background-color: rgb(248, 248, 248) !important; box-sizing: border-box;"><td style="background: rgb(225, 225, 225); box-sizing: border-box; padding: 5px 10px;"><b>Download Exploit: </b> <a href="https://www.exploit-db.com/download/39624">Source </a></td><td style="background: rgb(225, 225, 225); box-sizing: border-box; padding: 5px 10px;"><strong style="box-sizing: border-box;">Author:</strong> Ajith Kp</td><td style="background: rgb(225, 225, 225); box-sizing: border-box; padding: 5px 10px;"><br /></td></tr>
<tr style="background-color: rgb(248, 248, 248) !important; box-sizing: border-box;"><td style="box-sizing: border-box; padding: 5px 10px;"><br /><br /><br /><br /><br /><a href="http://www.hackthesec.co.in/">www.hackthesec.co.in</a></td><td colspan="2" style="box-sizing: border-box; padding: 5px 10px;"><br /></td></tr>
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Linux/x86_x64 - execve(/bin/sh) - 25 bytes

Linux/x86_x64 - execve(/bin/sh) - 25 bytes Download Exploit: Source Author: Ajith Kp www.hackthesec.co.in

Linux/x86_x64 - execve(/bin/bash) - 33 bytes

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Linux/x86_x64 - execve(/bin/bash) - 33 bytes</h1>
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<div class="exploit-meta clearfix" style="background-color: white; box-sizing: border-box; color: #666666; font-family: 'Open Sans', sans-serif; font-size: 14px; line-height: 24px;">
<div class="info" style="box-sizing: border-box; float: left;">
<table class="exploit_list" style="background-color: rgb(239, 239, 239) !important; border-radius: 3px !important; border-spacing: 1px; border: 1px solid rgb(221, 221, 221) !important; box-sizing: border-box; margin-bottom: 10px; margin-top: 10px; padding: 1px !important; width: 564px;"><tbody style="box-sizing: border-box;">
<tr style="background-color: rgb(248, 248, 248) !important; box-sizing: border-box;"><td style="box-sizing: border-box; padding: 5px 10px;"><br /></td><td style="box-sizing: border-box; padding: 5px 10px;"><br /></td><td style="box-sizing: border-box; padding: 5px 10px;"><br /></td></tr>
<tr style="background-color: rgb(248, 248, 248) !important; box-sizing: border-box;"><td style="box-sizing: border-box; padding: 5px 10px;"><strong style="box-sizing: border-box;">Download Exploit:</strong> <a href="https://www.exploit-db.com/download/39625" style="background-color: transparent; box-sizing: border-box; color: #337ab7; outline: 0px; text-decoration: none; transition-duration: 0.3s; transition-property: background-color, box-shadow, border, color, opacity;"><span class="fa fa-file-code-o" style="box-sizing: border-box; display: inline-block; font-family: "fontawesome"; font-size: inherit; font-stretch: normal; line-height: 1;"></span> Source</a> <span class="fa fa-times" style="box-sizing: border-box; display: inline-block; font-family: "fontawesome"; font-size: inherit; font-stretch: normal; line-height: 1;"></span></td><td style="box-sizing: border-box; padding: 5px 10px;"><strong style="box-sizing: border-box;">Author:</strong> Ajith Kp</td><td style="box-sizing: border-box; padding: 5px 10px;"><br /></td></tr>
<tr style="background-color: rgb(248, 248, 248) !important; box-sizing: border-box;"><td style="box-sizing: border-box; padding: 5px 10px;"><br />
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<a href="http://www.hackthesec.co.in/">www.hackthesec.co.in</a></td><td colspan="2" style="box-sizing: border-box; padding: 5px 10px;"><br /></td></tr>
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Linux/x86_x64 - execve(/bin/bash) - 33 bytes

Linux/x86_x64 - execve(/bin/bash) - 33 bytes Download Exploit: Source Author: Ajith Kp www.hackthesec.co.in