Tutor CTF

Contest Source: COMP6[84]41 CTF

In UNSW’s COMP6841, the tutors were kind enough to put together a CTF (which I affectionally refer to as the Tutor CTF) for us to do. This CTF consisted of 18 challenges for us to do, and loving a good challenge, I had a go at solving all of them. Here is the documentation of how I solved all 18 problems, the tools I used, as well as my thought process for each one. I hope you enjoy and are able to learn something from these writeups!

Links

• Reverse Engineering
  • (300 points) Executable text file
  • (750 points) Alice & Bob
• Misc
  • (100 points) Warmup
  • (150 points) bad_rand
  • (250 points) Shuffle
  • (500 points) bus buddies
• Pwn
  • (500 points) Chain
• Binary
  • (200 points) Cookie Monster
  • (300 points) shimmy
  • (450 points) tired
• Crypto
  • (140 points) substitution
  • (250 points) secedu
  • (300 points) substitute teacher
• Web
  • (300 points) Baby SSRF
• Forensics
  • (200 points) art_assignment
  • (200 points) block_game
  • (200 points) first_contact
  • (200 points) subliminal_messaging

Note that all flags have been replaced with “COMP6841{REDACTED}”. This is to discourage you from just blindly submitting the final answer, and to encourage you to follow along and learn something along the way.

Scoreboard

Finally, here’s the scoreboard proving my achievement as one of the top scorers: