Defcon quals: wwtw (a series of vulns)

Hey folks, This is going to be my final (and somewhat late) writeup for the Defcon Qualification CTF. The level was called "wibbly-wobbly-timey-wimey", or "wwtw", and was a combination of a few things (at least the way I solved it): programming, reverse engineering, logic bugs, format-string vulnerabilities, some return-oriented programming (for my solution), and Dr. […]

Defcon Quals: babyecho (format string vulns in gory detail)

Welcome to the third (and penultimate) blog post about the 2015 Defcon Qualification CTF! This is going to be a writeup of the "babyecho" level, as well as a thorough overview of format-string vulnerabilities! I really like format string vulnerabilities - they're essentially a "read or write anywhere" primitive - so I'm excited to finally […]

Defcon Quals: Access Control (simple reverse engineer)

Hello all, Today's post will be another write-up from the Defcon CTF Qualifiers. This one will be the level called "Access Client", or simply "client", which was a one-point reverse engineering level. This post is going to be mostly about the process I use for reverse engineering crypto-style code - it's a much different process […]

Defcon Quals: r0pbaby (simple 64-bit ROP)

This past weekend I competed in the Defcon CTF Qualifiers from the Legit Business Syndicate. In the past it's been one of my favourite competitions, and this year was no exception! Unfortunately, I got stuck for quite a long time on a 2-point problem ("wwtw") and spent most of my weekend on it. But I […]