Inode What You Did Last Summer
One of the security researchers at ESU needs help in their forensics of the ESU attack that occurred on 2022-07-27. They are asking if you can help them find the Inode of the file that was compromised and enabled the attackers to escalate their privileges to root.
Submit the flag as
The challenge file provided was an archive containing a file named esu-mem-20220727154029.dmp, which had magic-bytes indicating it was a memory dump acquired via Linux Memory Extractor.
$ xxd esu-mem-20220727154029.dmp | head -n1 00000000: 454d 694c 0100 0000 0010 0000 0000 0000 EMiL............
The archive also contained a file named Ubuntu_5.4.0-122-generic.zip which was a memory profile and needed to be in Volatility's plugin directory:
$ mv Ubuntu_5.4.0-122-generic.zip [VOLATILITY_HOME]/volatility/plugins/linux/ $ volatility2 --info | grep Ubuntu Volatility Foundation Volatility Framework 2.6.1 LinuxUbuntu_5_4_0-122-genericx64 - A Profile for Linux Ubuntu_5.4.0-122-generic x64
Finally, a quick validation test that everything is working as expected:
$ volatility2 --profile LinuxUbuntu_5_4_0-122-genericx64 -f esu-mem-20220727154029.dmp limeinfo Volatility Foundation Volatility Framework 2.6.1 Memory Start Memory End Size ------------------ ------------------ ------------------ 0x0000000000001000 0x000000000009efff 0x000000000009e000 0x0000000000100000 0x000000003ffd7ffe 0x000000003fed7fff
The challenge description is asking for the "…Inode of the file that was compromised and enabled the attackers to escalate their privileges to root", During the Escalation challenge we determined the file that was compromised was named "backup.py", so now it's just a matter of finding the file in the memory dump. The
linux_enumerate_files plugin lists files referenced by the filesystem cache and outputs three columns, Inode Address, Inode Number and Path. Running the plugin and grep'ing for 'backup.py' produces the Inode number needed to solve the challenge.
$ volatility2 --profile LinuxUbuntu_5_4_0-122-genericx64 -f esu-mem-20220727154029.dmp linux_enumerate_files | grep -F "backup.py" Volatility Foundation Volatility Framework 2.6.1 0xffff959183253cd8 788070 /opt/backup.py
The accepted flag was:
Leave a comment