RHEL 7 and Centos7 Root Password recovery procedure

<div dir="ltr" style="text-align: left;" trbidi="on"> <h1 class="entry-title post-title" style="background-color: white; border: 0px; font-family: Arial, Helvetica, sans-serif; font-stretch: inherit; line-height: 1em; margin: 0.5em 0px; padding: 0px; vertical-align: baseline; word-wrap: break-word;"> <span style="color: #990000; font-size: large;"><u><i>RHEL7/CENTOS7: Interrupt the boot process in order to gain access to a system.</i></u></span></h1> <div> <div class="separator" style="clear: both; text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgHLpe_9uUaPwqHqQRdPlX5dYbVZ5yChcYfD_LyuVgxPoTUaf6IEzSL1aOuQProwdzNdOtlDMnmoKojDWzMuoQYR6Oz4-D3jjX1UQXA5W_HZOEvI6W_YJKmrzyKXOu-aMEjGdTBY_QxjQ4J/s1600/recover_root_password.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgHLpe_9uUaPwqHqQRdPlX5dYbVZ5yChcYfD_LyuVgxPoTUaf6IEzSL1aOuQProwdzNdOtlDMnmoKojDWzMuoQYR6Oz4-D3jjX1UQXA5W_HZOEvI6W_YJKmrzyKXOu-aMEjGdTBY_QxjQ4J/s320/recover_root_password.png" width="320" /></a></div> <div style="background-color: white; border: 0px; font-family: Arial, Helvetica, sans-serif; font-size: 14px; font-stretch: inherit; line-height: 21px; margin-bottom: 1.6em; margin-top: 1.6em; padding: 0px; vertical-align: baseline; word-wrap: break-word;"> In <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;"><a href="http://www.hackthesec.co.in/search/label/RHEL" target="_blank">RHEL</a> 7</span>, the procedure to get access to a system during the boot process and modify the root password has changed because of the adoption of <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">Systemd</span>.<br /><span style="color: white;"><a href="http://www.hackthesec.co.in/2016/02/rhel-7-and-centos7-root-password.html" target="_blank">RHEL 7 Root Password recovery procedure</a><br /><a href="http://www.hackthesec.co.in/2016/02/rhel-7-and-centos7-root-password.html" target="_blank">Centos7  Root Password recovery procedure</a></span><br />There were several procedures floating around to recover the root password. Some were working with physical servers but not with virtual machines, some the other way around.</div> <div style="background-color: white; border: 0px; font-family: Arial, Helvetica, sans-serif; font-size: 14px; font-stretch: inherit; line-height: 21px; margin-bottom: 1.6em; margin-top: 1.6em; padding: 0px; vertical-align: baseline; word-wrap: break-word;"> The following procedure works all the time.</div> <h2 style="background-color: white; border: 0px; font-family: Arial, Helvetica, sans-serif; font-size: 2.25em; font-stretch: inherit; line-height: 1em; margin: 0.75em 0px; padding: 0px; vertical-align: baseline; word-wrap: break-word;"> <span style="color: #0b5394;">Procedure</span></h2> <div style="background-color: white; border: 0px; font-family: Arial, Helvetica, sans-serif; font-size: 14px; font-stretch: inherit; line-height: 21px; margin-bottom: 1.6em; margin-top: 1.6em; padding: 0px; vertical-align: baseline; word-wrap: break-word;"> At the beginning of the boot process, at the <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">GRUB 2</span> menu, type the <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">e</span> key to edit.</div> <div style="background-color: white; border: 0px; font-family: Arial, Helvetica, sans-serif; font-size: 14px; font-stretch: inherit; line-height: 21px; margin-bottom: 1.6em; margin-top: 1.6em; padding: 0px; vertical-align: baseline; word-wrap: break-word;"> Then, go to the kernel line (the line starting with <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">linux16</span>) and add the following statements at the end:</div> <pre style="background: rgb(244, 244, 244); border-color: rgb(170, 170, 170) rgb(170, 170, 170) rgb(204, 204, 204); border-radius: 2px; border-style: solid; border-width: 1px; box-shadow: rgb(255, 255, 255) 0px 1px 0px, rgba(0, 0, 0, 0.2) 0px 1px 1px inset; box-sizing: border-box; font-family: monospace, serif; font-size: 14px; font-stretch: inherit; height: auto; line-height: 21px; outline: none; overflow-x: auto; padding: 6px 10px; vertical-align: middle; width: 605.484px; word-wrap: normal;"><span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;"><span style="color: #555555;">rd.break </span><span style="color: #351c75;">enforcing</span><span style="color: #555555;">=0</span></span></pre> <div style="background-color: white; border: 0px; font-family: Arial, Helvetica, sans-serif; font-size: 14px; font-stretch: inherit; line-height: 21px; margin-bottom: 1.6em; margin-top: 1.6em; padding: 0px; vertical-align: baseline; word-wrap: break-word;"> Caution: The keys to press are those of a <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">US</span> keyboard (querty).<br />Note: <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">rd.break</span> asks for a break at an early stage of the boot process. <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">enforcing=0</span> puts the system into <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">SELinux Permissive</span> mode.</div> <div style="background-color: white; border: 0px; font-family: Arial, Helvetica, sans-serif; font-size: 14px; font-stretch: inherit; line-height: 21px; margin-bottom: 1.6em; margin-top: 1.6em; padding: 0px; vertical-align: baseline; word-wrap: break-word;"> Press <span style="border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">Ctrl x</span> to resume the boot process.</div> <div style="background-color: white; border: 0px; font-family: Arial, Helvetica, sans-serif; font-size: 14px; font-stretch: inherit; line-height: 21px; margin-bottom: 1.6em; margin-top: 1.6em; padding: 0px; vertical-align: baseline; word-wrap: break-word;"> Then, mount the <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">/sysroot</span> partition as read/write:</div> <pre style="background: rgb(244, 244, 244); border-color: rgb(170, 170, 170) rgb(170, 170, 170) rgb(204, 204, 204); border-radius: 2px; border-style: solid; border-width: 1px; box-shadow: rgb(255, 255, 255) 0px 1px 0px, rgba(0, 0, 0, 0.2) 0px 1px 1px inset; box-sizing: border-box; font-family: monospace, serif; font-size: 14px; font-stretch: inherit; height: auto; line-height: 21px; outline: none; overflow-x: auto; padding: 6px 10px; vertical-align: middle; width: 605.484px; word-wrap: normal;"><span style="color: #555555;">switch_root:/# </span><span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;"><span style="color: #351c75;">mount –o remount,rw /sysroot</span></span></pre> <div style="background-color: white; border: 0px; font-family: Arial, Helvetica, sans-serif; font-size: 14px; font-stretch: inherit; line-height: 21px; margin-bottom: 1.6em; margin-top: 1.6em; padding: 0px; vertical-align: baseline; word-wrap: break-word;"> Execute the <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">chroot</span> command on the <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">/sysroot</span> partition:</div> <pre style="background: rgb(244, 244, 244); border-color: rgb(170, 170, 170) rgb(170, 170, 170) rgb(204, 204, 204); border-radius: 2px; border-style: solid; border-width: 1px; box-shadow: rgb(255, 255, 255) 0px 1px 0px, rgba(0, 0, 0, 0.2) 0px 1px 1px inset; box-sizing: border-box; font-family: monospace, serif; font-size: 14px; font-stretch: inherit; height: auto; line-height: 21px; outline: none; overflow-x: auto; padding: 6px 10px; vertical-align: middle; width: 605.484px; word-wrap: normal;"><span style="color: #555555;">switch_root:/# </span><span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;"><span style="color: #555555;">chroot /</span><span style="color: #351c75;">sysroot</span></span></pre> <div style="background-color: white; border: 0px; font-family: Arial, Helvetica, sans-serif; font-size: 14px; font-stretch: inherit; line-height: 21px; margin-bottom: 1.6em; margin-top: 1.6em; padding: 0px; vertical-align: baseline; word-wrap: break-word;"> Change the <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">root</span> password:</div> <pre style="background: rgb(244, 244, 244); border-color: rgb(170, 170, 170) rgb(170, 170, 170) rgb(204, 204, 204); border-radius: 2px; border-style: solid; border-width: 1px; box-shadow: rgb(255, 255, 255) 0px 1px 0px, rgba(0, 0, 0, 0.2) 0px 1px 1px inset; box-sizing: border-box; font-family: monospace, serif; font-size: 14px; font-stretch: inherit; height: auto; line-height: 21px; outline: none; overflow-x: auto; padding: 6px 10px; vertical-align: middle; width: 605.484px; word-wrap: normal;"><span style="color: #555555;">sh-4.2# <span style="border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">passwd root</span> Changing password for user root. New passwd: <b>mypassword</b> Retype new password: <b>mypassword</b> </span><span style="color: #351c75;">passwd: all authentication token updated successfully. </span><span style="color: #555555;">sh-4.2# </span><span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; color: #555555; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">exit </span><span style="color: #555555;">exit switch_root:/# </span><span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;"><span style="color: #351c75;">exit</span></span><span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; color: #555555; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;"> </span><span style="color: #555555;">logout</span></pre> <div style="background-color: white; border: 0px; font-family: Arial, Helvetica, sans-serif; font-size: 14px; font-stretch: inherit; line-height: 21px; margin-bottom: 1.6em; margin-top: 1.6em; padding: 0px; vertical-align: baseline; word-wrap: break-word;"> Connect to your server at the console (don’t reboot now!) with the <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">root</span> user and the new password:</div> <pre style="background: rgb(244, 244, 244); border-color: rgb(170, 170, 170) rgb(170, 170, 170) rgb(204, 204, 204); border-radius: 2px; border-style: solid; border-width: 1px; box-shadow: rgb(255, 255, 255) 0px 1px 0px, rgba(0, 0, 0, 0.2) 0px 1px 1px inset; box-sizing: border-box; font-family: monospace, serif; font-size: 14px; font-stretch: inherit; height: auto; line-height: 21px; outline: none; overflow-x: auto; padding: 6px 10px; vertical-align: middle; width: 605.484px; word-wrap: normal;"><span style="color: #555555;">... [  OK  ] Started Network Manager Script Dispatcher Service. [  OK  ] Started Crash recovery kernel arming. [  OK  ] Reached target Multi-User System. </span><span style="color: #0b5394;">CentOS Linux 7 (Core) </span><span style="color: #555555;">Kernel 3.10.0-229.14.1.el7.x86_64 on an x86_64 vm login: </span><span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; color: #555555; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">root</span><span style="color: #555555;"> Password: </span><b style="color: #555555;">mypassword</b><span style="color: #555555;"> </span></pre> <div style="background-color: white; border: 0px; font-family: Arial, Helvetica, sans-serif; font-size: 14px; font-stretch: inherit; line-height: 21px; margin-bottom: 1.6em; margin-top: 1.6em; padding: 0px; vertical-align: baseline; word-wrap: break-word;"> Then type:</div> <pre style="background: rgb(244, 244, 244); border-color: rgb(170, 170, 170) rgb(170, 170, 170) rgb(204, 204, 204); border-radius: 2px; border-style: solid; border-width: 1px; box-shadow: rgb(255, 255, 255) 0px 1px 0px, rgba(0, 0, 0, 0.2) 0px 1px 1px inset; box-sizing: border-box; font-family: monospace, serif; font-size: 14px; font-stretch: inherit; height: auto; line-height: 21px; outline: none; overflow-x: auto; padding: 6px 10px; vertical-align: middle; width: 605.484px; word-wrap: normal;"><span style="color: #555555;"># </span><span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;"><span style="color: #351c75;">restorecon /etc/shadow</span><span style="color: #555555;"> </span></span><span style="color: #555555;"># </span><span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; color: #555555; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">reboot</span></pre> <div style="background-color: white; border: 0px; font-family: Arial, Helvetica, sans-serif; font-size: 14px; font-stretch: inherit; line-height: 21px; margin-bottom: 1.6em; margin-top: 1.6em; padding: 0px; vertical-align: baseline; word-wrap: break-word;"> If you strictly follow this procedure, you don’t need to force a <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">SELinux</span> relabel (# <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">touch /.autorelabel</span>) or load the <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">SELinux</span> policy (# <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">/usr/sbin/load_policy -i</span>).</div> <div style="background-color: white; border: 0px; font-family: Arial, Helvetica, sans-serif; font-size: 14px; font-stretch: inherit; line-height: 21px; margin-bottom: 1.6em; margin-top: 1.6em; padding: 0px; vertical-align: baseline; word-wrap: break-word;"> You don’t even need to reboot at the end! In this case, type # <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-family: inherit; font-stretch: inherit; font-style: inherit; font-variant: inherit; font-weight: 700; line-height: inherit; margin: 0px; padding: 0px; vertical-align: baseline;">setenforce enforcing<br /><a href="http://www.hackthesec.co.in/" style="color: #999999; font-family: 'Roboto Slab'; font-size: 16px; font-weight: normal; line-height: 28px; text-decoration: none;" target="_blank">HackTheSec</a><br style="color: #333333; font-family: 'Roboto Slab'; font-size: 16px; font-weight: normal; line-height: 28px;" /><a href="https://www.twitter.com/hackthesecurity" style="color: #999999; font-family: 'Roboto Slab'; font-size: 16px; font-weight: normal; line-height: 28px; text-decoration: none;" target="_blank">HackTheSecTwitter</a><br style="color: #333333; font-family: 'Roboto Slab'; font-size: 16px; font-weight: normal; line-height: 28px;" /><a href="http://facebook.com/htsecu" style="color: #999999; font-family: 'Roboto Slab'; font-size: 16px; font-weight: normal; line-height: 28px; text-decoration: none;" target="_blank">HackTheSecFacebook</a><br style="color: #333333; font-family: 'Roboto Slab'; font-size: 16px; font-weight: normal; line-height: 28px;" /><a href="http://www.hackthesec.co.in/" style="color: #999999; font-family: 'Roboto Slab'; font-size: 16px; font-weight: normal; line-height: 28px; text-decoration: none;">www.hackthesec.co.in</a></span></div> </div> </div>

RHEL 7 and Centos7 Root Password recovery procedure

RHEL7/CENTOS7: Interrupt the boot process in order to gain access to a system. In  RHEL 7 , the procedure to get access to a system ...

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