This is my blog. There are many like it, but this one is mine.
This page contains all the past CTF challenges that I have authored. You can use these to practice, to try and correlate the pop culture references, or to just entertain yourself with the write-ups.
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Archived Comments:
Me
Nice post but I wanna know how do i fing this flag for CircleCityCon 2014 Level3? Any write-up?
Thx
exocron
Unfortunately, no one has created a writeup that I know of. I try not to post writeups for the challenges that I created because it’s better from a player’s perspective instead of an author’s. I’m fairly certain that all of my challenges at CircleCityCon got solved by at least one person, but since it’s been a year, I might write them up myself once I finish porting my blog over to a new system.
The goal of this challenge was to prevent players from using decompilers and using a bytecode-oriented tool instead. One of the pet peeves that I and the other Android challenge authors had from the previous year was that people were just tossing our challenges into dex2jar and running them on the PC, which works well for simple apps like these but doesn’t always work for the complicated apps of the real world. The dalvik bytecode has been slightly mutated to break most decompilers without breaking the functionality of the app. So, to start, you would want a tool that operates on dalvik bytecode, like smali. Once the class is baksmai’ed, it should be pretty obvious what to patch to get the flag.