Jul 25, 2017

What is Cracknet? As a part of the SecTalks May CTF I built a .Net reverse engineering challenge, Cracknet. I’ve since made this available on Github, here. Although it’s possible to complete this challenge by bypassing a JMP instruction in assembly the intention of this challenge was to introduce participants to decompiling .Net applications by patching the application. Exploring CrackNet functionality When you first open CrackNet you’re presented with the following:

Mar 8, 2017

Category: Coding Points: 400 Solves: 7 Description: ctf.crikeycon.com:43981 Enumeration Before doing anything else on the host since we were provided with an unual port and address I attempted to ncat to it, receiving the following: Identifying the core problem Since the math is impossible there’s likely a trick here. With that in mind I figure we need to overload an operator (integer overflow) and try passing a large number as input:

Mar 8, 2017

Category: Coding Points: 300 Solves: 14 Description: crikeyconctf.dook.biz:23776 Enumeration Before doing anything else on this host I attempted to connect to it, receiving the following: The time between being presented with the challenge and receiving a timeout was a mere two seconds. Although handy with a calculator this wouldn’t be possible without a script/bot. I also noted that the response and timing to answer didn’t change on a second connection, but the base operator did.