Loginator

#

Points: 50

Solves: 153

02 92 a8 06 77 a8 32 3f 15 68 c9 77 de 86 99 7d 08 60 8e 64 77 be ba 74 26 96 e7

We are given a binary that obfuscates some text. Giving it BITSCTF returned

❯ ./loginator.out BITSCTF
02 92 a8 06 77 a8 32

which matches the first few bytes of the description. This now turns into a bruteforcing problem

With the help of my solve script I manually got each character and recreated the flag, letter by letter. (there’s probably a better way to do this, but don’t look at me, idk python)

from pwn import process
import string

for i in string.printable:
    payload = f"BITSCTF\x7bC4ND4C3_L0G1C_W0RK{i}"
    proc = process(["./loginator.out"] + [payload])
    res = proc.recvline().decode().strip()
    print(f"[{i}] trying string {payload}")
    if res == "02 92 a8 06 77 a8 32 3f 15 68 c9 77 de 86 99 7d 08 60 8e 64 77 be ba 74 26 96 e7":
        break
    proc.close()

I had to escape that first { with \x7b for some reason, I’m not sure what was up with that

BITSCTF{C4ND4C3_L0G1C_W0RK}