TSGCTF2020 Reverse-ing

Published:

Even though this is a reversing challenge, I thought I’d try to do the least amount of work and use Angr. Because this was labeled as an easy challenge, writing the angr solve script was also easy.

Walkthrough

First, I ran file reversing to check whether or not the executable was stripped. This returned

reversing: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, not stripped

I also did a cursory check of the binary using Binary Ninja to make sure there was nothing too complicated going on which would make the symbolic execution take too long.

With these done, I began writing the python script.

Angr Solve

Running this gives us the solution!

Flag: TSGCTF{S0r3d3m0_b1n4ry_w4_M4wa77e1ru} Time elapsed: 137.10 seconds