An optimization for the finite field multiplication on 128-bit elements for AES-GCM exists whose explanation was not published, preventing any further application with different parameters. We reverse engineered the result to 1) get the explanation and 2) be able to apply it with other parameters.

Since Windows XP SP2, the Windows firewall is deployed and enabled by default in every Microsoft Windows operating system. Starting with Windows Vista the firewall relies on a set of API and services called the Windows Filtering Platform (WFP). Although used by almost every Windows OS, WFP is still one of the relatively unknown beast that lies in the kernel. In this post we will see how the firewall manages its persistent state.

We recently looked at the Obfuscator-LLVM project in order to test its different protections. Here are our results, and explanations on how we deal with obfuscation.

Modern OSes have a feature that mitigates the exploitation of stack based buffer overflows. It basically works by writing a "cookie" value before the return address in the stack in the prologue of a function and checking it before the function returns (for further information, see and ). This article talks about how this mitigation has been enforced in Windows 8.

C++ is well-known to be tedious to analyze, the use of both inheritance and polymorphism (i.e. virtual method) makes the compiler generate indirect calls. Usually, this kind of assembly code forces the reverse engineer to execute the code in order to figure out the destination of a call. In fact, we are looking for the VFT (Virtual Function Table). This table contains all virtual methods for a specific instance of a class. This article shows how to retrieve this information to make the analysis of a C++ software easier.

Ok, here it is, the new version of qb-sync with lots of new features: new commands, sync multiple IDBs (and thus modules) with a debugger, Windbg remote control shortcuts in IDA, etc.

qb-sync is an open source tool to add some helpful glue between IDA Pro and Windbg. Its core feature is to dynamically synchronize IDA's graph windows with Windbg's position.

In the previous blog post we have seen how the ApiSetSchema was set up during boot time by the system. In this post we’ll see what the structure of the ApiSetSchema is and finally in the next blog post we’ll see how it is used in user-land and kernel-land.

This series of blog posts is about the new dynamic link libraries (DLLs) layout in Windows 6.x operating systems, where functions are now exported by new modules but the real implementation is located elsewhere. Static analysis tools might have problems dealing with this DLL restructuring. This blog post is aimed at presenting what is this new scheme, how it is implemented and how it is possible to leverage it so it can be used by static analysis tools.