RHEL7 Gain Acces To root User interrupting boot process - Tech Arkit

hi friends welcome to Tech Arkit YouTube channel my name is Ravi. In this video session we are going to see that how to interrupt boot process and get the access to the any Linux machine, whenever you have a physical access to the server.



Let's see this so how you can do that. so first of all here I have the Linux machine switched-on. So i have a physical access to this machine when I click over here so I say that enter and I type the password over here but unfortunately the password is wrong. So I would like to reset this password or I would like to gain the access to the machine. I do not have the password in hand let's do that how you can get it.



so first of all I am going to reboot this machine, click restart, while machine has been restarting so I have to press spacebar to stop over here.



The kernel process stopped over here. here in the kennel step it self what you can do is that so I can simply click are you sick and simply Say e for edit which means that I'm going to edit this kernel lines to interrupt the boot process.



I just edited using the e and go down over here and whereever you see that Linux16 the line ok simply go to the end of that line and add rd.break console equal to tty1 so whenever you add this one what happens so whenever you add this one it says that you are entering your breaking this process and entering into the single user mode.



 by entering into the single user mode you get the access to the that machine so which means that you are in the single user mode It does not ask you any username and password just enter into the root directly ok.



 so now just press control x now the machine boot process would be interrupted and enter into the single user mode ok now which got into the single user mode directly can see that hash value over here to you which means that which is into root.



type Mount command and see that all this files has been mounted as read only actually. so not mounts really into the rewrite options for here OK.



are else you can also see the mount /sysroot over here already mounted and it is busy looks like ok so maybe you can grep /sysroot ok the root file system has been mounted but which shows here it is that /sysroot is in read only so whenever you have read only file system you cannot edit anything.



 it should be read write then only I can write anything on this file system. inorder to gain inorder to convert this into read/write just do this month -o remount,rw /sysroot and read/write this partition re-mount this mount point. With read write access /sysroot



now you can see that using the above command now it is rewrite. just convert this /sysroot into actual root using the convert chroot innocent change chroot /sysroot now it becomes an root now type command called passwd which will ask you for the new password to enter the can now change the password over here so the password authentication has been changed.



now you can rebot the machine but what happened here is that the by default RHEL7 enables the SELinux so without relabling all your selinux policy are the contexts then you can not get the access really to the machine so in order to gain the success and reliable all selinux related stuff then what have to do is that you have to create empty file in the / (slash) so that it relabels automatically so in order to do that create touch / dat auto relabel so be careful because if you mispell or if you do not properly create this file you cannot get the access are you cannot gain access to the machine.



so in order to do that you have to be very careful whenever you are creating this file so confirm that the file has been created and exit from the process whenever you do exit 2 times it reboots the machine it relabels everything from the the contexts of the selinux then it starts the machine then you can enter into the username and password so that you will get the access.



so now your PC has been turned on we can go to the user and type the password so actually reset the password called root user over here and enter the password. that's it you got into the machine see this your machine now you are into root user



that's it so you simply gain this access by interrupting your kernel process whenever you have the physical access to that machine



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