BSidesSF CTF: b-64-b-tuff Walkthrough

This week I was part of team "NeverTry" who competed in the BSidesSF online capture the flag. As far as CTF's go, this was a fun one, taking place over 2 days there were a range of cool puzzles and flags to find. Over a series of upcoming posts I'll be running through the solutions for a number of my favourite challenges, starting with b-64-b-tuff. This challenge started with a simple application which receives binary shellcode over the network, and executes th... Read More »

ROP Primer - Walkthrough of Level 2

In the final post in this series, we'll be looking at Level 2, the last level of ROP Primer from VulnHub. This level gives a very simple program, similar to the first challenge that we faced in Level 0. The source of the application is as follows... Read More »

ROP Primer - Walkthrough of Level 1

Continuing from the previous post which shows a solution for Level 0, we are going to look at Level 1 of ROP Primer from VulnHub. Level 1 is a server application, which suffers from a typical buffer overflow. Reviewing the application source provided by the challenge, we can see that the overflow vector is within the following code... Read More »

ROP Primer - Walkthrough of Level 0

I recently found Vulnhub ROP Primer, which is a brilliant playground for refreshing your Linux ROP skills. To try and share some of the techniques I used to solve these challenges, I'm completing a series of writeups detailing the steps to solve each level. In typical Vulnhub style we start with a virtual machine which runs a number of services alongside a HTTP server documenting the 3 levels of difficulty. This post will be looking at Level 0... Read More »

Radare2 - Using Emulation To Unpack Metasploit Encoders

Radare2 is an open source reverse engineering framework, and is quickly becoming one of my favourite tools when picking apart malware or looking at CTF binaries. I was recently introduced to Radare’s ESIL (Evaluable Strings Intermediate Language), which is a way of representing instructions in a forth like language, and allows emulation of machine instructions in Radare’s ESIL VM. To help understand this functionality, lets look at some examples from the radare2 book... Read More »