Tag: TJCTF
TJCTF 2018
Aug. 12, 2018
I played TJCTF as part of the team pearl, and we solved every challenge, placing second overall. The Abyss was a Python jail challenge worth 160 points — since I really enjoy this type of challenge, I figured it was worth writing up.
The Abyss
You are able to netcat to a server where you get a Python prompt that execs whatever you enter. However, what you can run is heavily filtered and dangerous functions are filtered from builtins.
The biggest restriction is nothing with __, which prevents most Python jail escapes from working. The solution involves creating a code object, and using that to create a function object that you can run to get the flag.
