Type your comment> @lobo09 said:
For those who are doing the challenge but don’t wanna spoil themselves with writeups (like me): the library you want to use for the exploit to work is not in the database anymore. Don’t get foolishly stuck like I did. In any case, you understand what you’re doing and it’s not your fault.
Here you can get it (since this is retired content I guess I can do this):
2.23-0ubuntu11 : libc6 : amd64 : Xenial (16.04) : Ubuntu
For anyone working on this… I first looked in https://libc.blukat.me/ to find the version and as @lobo09 mentioned it’s not there. Then I saw mention of a GitHub libc-database. Lucky for me, they are hosting it at https://libc.rip/
It took 1/2 a dozen tries to find the right library but it’s there. The 2.23-0ubuntu11 didn’t work on my instance.
John Hammond and IppSec have some great videos on YouTube using PwnTools for an exploit like this. They won’t show you this exact challenge but rather the workflow.