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GSEC · Question #164

You work as a Linux technician for Tech Perfect Inc. You have lost the password of the root. You want to provide a new password. Which of the following steps will you take to accomplish the task?

The correct answer is D. Reboot the computer in run level 1. In Linux, run level 1 (single-user mode) provides a root shell without requiring authentication, allowing a lost root password to be reset.

Linux and Cryptography

Question

You work as a Linux technician for Tech Perfect Inc. You have lost the password of the root. You want to provide a new password. Which of the following steps will you take to accomplish the task?

Options

  • AThe password of the root user cannot be changed.
  • BUse the PASSWD root command.
  • CReboot the computer in run level 0. Use INIT=/bin/sh as a boot option.
  • DReboot the computer in run level 1.

How the community answered

(37 responses)
  • A
    14% (5)
  • B
    5% (2)
  • C
    3% (1)
  • D
    78% (29)

Why each option

In Linux, run level 1 (single-user mode) provides a root shell without requiring authentication, allowing a lost root password to be reset.

AThe password of the root user cannot be changed.

The root password can always be reset through recovery methods such as single-user mode or a live boot environment - it is never permanently irrecoverable.

BUse the PASSWD root command.

The correct command syntax is lowercase 'passwd root'; however, even with correct syntax, running this command requires an authenticated root session, which is unavailable when the root password is lost.

CReboot the computer in run level 0. Use INIT=/bin/sh as a boot option.

Run level 0 is the halt or shutdown state - booting to run level 0 powers off the system immediately and does not provide a shell for password recovery.

DReboot the computer in run level 1.Correct

Rebooting into run level 1 starts Linux in single-user mode, which drops to a root shell without prompting for a password. From this shell, the administrator can execute the 'passwd' command to set a new root password and then reboot into the normal multi-user run level.

Concept tested: Linux root password recovery using single-user mode

Source: https://man7.org/linux/man-pages/man8/init.8.html

Topics

#Linux root password#run level 1#single user mode#password recovery

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