Brooklynt Overflow Recently Competed in HackIM CTF. This is a writeup of the vuln4 service. The author was kind enough to provide source to this challenge which is nice but ultimately not necessary or terribly helpful.

Brooklynt Overflow Recently Competed in HackIM CTF. This is a writeup of the vuln3 service. Vuln3 is a service exposed to the Internet via xinetd or something similar. It accepts input from you writes it to the stack, parses it and performs actions based on it. It does this until you disconnect. The important parts of user input are dwords at offset 0x28 and 0x50. The dword at offset 0x28 tell the service what operation to perform. The dword at offset 0x50 is used only when you ask the service to allocate some memory for you, it is then used as the argument to malloc.

Exploitation 200 HackIM

This challenge was relatively straightforward, especially given the fact that we have access to the source.