Category: General

  • Detecting Hypervisor-assisted Hooking

    I recently started to experiment with hypervisors and their use for bypassing anti-cheat or anti-tampering systems. This post will describe the concept of hypervisor-assisted hooking and a few simple approaches to detect such hooks. What is a hypervisor? In short: A hypervisor allows to run virtual machines with hardware acceleration. The concept of hypervisors in […]

  • Google CTF 2019 – JIT

    Thanks to Rektinator and TwistedFate for helping me solve this challenge. JIT was one of Google’s pwnable challenges. It implements an artificial assembly language, which gets jit-compiled into x64 assembly. An example program looks like this: It supports basic instructions to move, add and subtract, jump and compare values. Two files were given: compiler.c and […]

  • 9os – Nyan Cat ‘Operating System’

    For our graduation-party at school two years ago, a friend of mine, Olrik, and I decided to play the Nyan Cat theme on all PCs at school. With the name 9os, we started writing the entire project using 16bit x86 assembly. The task was to draw the rainbow behind the cat, then the cat itself, […]

  • Harpoon – Yet another ARP posioning tool

    After having started to use libraries like libpcap or WinDivert, I got curious about low-level networking protocols like Ethernet, IP, ICMP, ARP, TCP or UDP. Especially the Address Resolution Protocol (ARP) fascinated me, as I have previously used tools like Ettercap or Cain & Abel to experiment with Man-in-the-middle attacks using ARP poisoning, however, I […]

  • Game hacking reinvented? – A cod exploit

    A few years ago, I became aware of a security issue in most Call of Duty games. Although I did not discover it myself, I thought it might be interesting to see what it could be used for. Without going into detail, this security issue allows users playing a Call of Duty match to cause […]