Breaking ledgerctf's AES white-box challenge

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 …

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beVX challenge on the operation table

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 …

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Debugger data model, Javascript & x64 exception handling

Introduction

The main goal of today's post is to show a bit more of what is now possible with the latest Windbg (currently branded "WinDbg Preview" in the Microsoft store) and the time travel debugging tools that Microsoft released a few months ago. When these finally got released, a bit …

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Binary rewriting with syzygy, Pt. I

Introduction

Binary instrumentation and analysis have been subjects that I have always found fascinating. At compile time via clang, or at runtime with dynamic binary instrumentation frameworks like Pin or DynamoRIO. One thing I have always looked for though, is a framework able to statically instrument a PE image. A …

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happy unikernels

Intro

Below is a collection of notes regarding unikernels. I had originally prepared this stuff to submit to EkoParty’s CFP, but ended up not wanting to devote time to stabilizing PHP7’s heap structures and I lost interest in the rest of the project before it was complete. However …

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Token capture via an llvm-based analysis pass

Introduction

About three years ago, the LLVM framework started to pique my interest for a lot of different reasons. This collection of industrial strength compiler technology, as Latner said in 2008, was designed in a very modular way. It also looked like it had a lot of interesting features that …

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Keygenning with KLEE

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 …

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Spotlight on an unprotected AES128 white-box implementation

Introduction

I think it all began when I've worked on the NSC2013 crackme made by @elvanderb, long story short you had an AES128 heavily obfuscated white-box implementation to break. The thing was you could actually solve the challenge in different ways:

  1. the first one was the easiest one: you didn't …
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Taming a wild nanomite-protected MIPS binary with symbolic execution: No Such Crackme

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 …

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Dissection of Quarkslab's 2014 security challenge

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 …

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