Introduction

About a month ago, my mate b0n0n was working on the ledgerctf puzzles and challenged me to have a look at the ctf2 binary. I eventually did and this blogpost discusses the protection scheme and how I broke it. Before diving in though, here is a bit of background …

Introduction

About two weeks ago, my friend mongo challenged me to solve a reverse-engineering puzzle put up by the SSD team for OffensiveCon2018 (which is a security conference that took place in Berlin in February). The challenge binary is available for download here and here is one of the original …

Introduction

In the past weeks I enjoyed working on reversing a piece of software (don't ask me the name), to study how serial numbers are validated. The story the user has to follow is pretty common: download the trial, pay, get the serial number, use it in the annoying nag …

As last year, the French conference No Such Con returns for its second edition in Paris from the 19th of November until the 21th of November. And again, the brilliant Eloi Vanderbeken & his mates at Synacktiv put together a series of three security challenges especially for this occasion. Apparently, the …

Introduction

As the blog was a bit silent for quite some time, I figured it would be cool to put together a post ; so here it is folks, dig in!

The French company Quarkslab recently released a security challenge to win a free entrance to attend the upcoming HITBSecConf conference …

Introduction

I am currently playing with pool-based memory corruption vulnerabilities. That’s why I wanted to program a PoC exploit for the vulnerability presented by Tarjei Mandt during his first talk “Kernel Pool Exploitation on Windows 7” [3]. I think it's a good exercise to start learning about pool overflows …

Introduction

Kryptonite was a proof-of-concept I built to obfuscate codes at the LLVM intermediate representation level. The idea was to use semantic-preserving transformations in order to not break the original program. One of the main idea was for example to build a home-made 32 bits adder to replace the add …

Introduction

Yesterday afternoon, I was peacefully coding some stuff you know but I couldn't make my code working. As usual, in those type of situations you fire up your debugger in order to understand what is going on under the hood. That was a bit weird, to give you a …

Introduction

Sometimes, when you are reverse-engineering binaries you need somehow to measure, or just to have an idea about how much "that" execution is covering the code of your target. It can be for fuzzing purpose, maybe you have a huge set of inputs (it can be files, network traffic …

Introduction

Some months ago I came across a strange couple of functions that was kind of playing with a finite-state automaton to validate an input. At first glance, I didn't really notice it was in fact a regex being processed, that's exactly why I spent quite some time to understand …