csaw21

Writeups for CSAW 2021 CTF

View on GitHub

A Different Type of Serial Key

Writeup by: USERNAME

Team: OnlyFeet

Writeup URL: GitHub


Attached are serial captures of two different uploads to an embedded device. One of these uploads is a key and the other is a function block. Your goal is to decode the serial traffic, extract the key and function block, and use these to find the flag. The flag will be in format flag{}.
Author: CISA

Initial Research

Word.

$ echo 'thingz'
thingz

Version Mismatches

Wordsz.

some output

Ancient History or Stegosarus Time

Moar Words

$ cat commands.txt
commands1
$ nmap 1.2.3.4
...

Victory

Submit the flag and claim the points:

flag{flag-goes-here}