In one of Quarkslab's projects, we came across the issue of randomizing a large set of integers, described as a list of disjoint intervals. These intervals can be represented as a sorted list of integers couples, like this one: \([1, 4], [10, 15], [17, 19], \dots\). The idea is to randomly and uniquely select numbers across these intervals, giving a shuffled list of numbers that belong to them. For instance, \([1,10,18,4,3,11,15,17,19,12,14,13,2]\) is a possible output. Moreover, each possible permutation of the integers set should have equal probability of appearance. If you're just interested in the final library that "do the job", go directly to the implementation section to download the leeloo C++ open-source library on Github !

The new jailbreak for iOS 6.1, named Evasi0n, is detailed in this article, thanks to Braden Thomas. A few more details are needed regarding the very end on the page signing cancelation. Actually, in order to evade code signed verification, the amfi.dylib is cleverly structured. The idea is as follow: force the MISValidateSignature (which returns the status of code signing verification) to always return 0. That way, one will be able to execute any unsigned code. Hence, this raises 2 questions: How to force MISValidateSignature to always return 0? How to pass the code signed verification for amfy.dylib?

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.

What was really stunning about Stuxnet and its cousins was it was "open source". Once the sample was captured, it was big to analyze, but none of its embedded secrets could escape a malware analyst. And it had many secrets! From an engineering point of view, the architecture and design are clean and efficient, which makes Stuxnet a good example to learn how to design malware. From an intelligence point of view, knowing what is targeted is valuable. For a money point of view, considering how governments are racing to buy 0 days, Stuxnet was above expensive. And all this was wasted because the payload was unprotected!

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.

Quarks PwDump is new open source tool to dump various types of Windows credentials: local account, domain accounts, cached domain credentials and bitlocker. The tool is currently dedicated to work live on operating systems limiting the risk of undermining their integrity or stability. It requires administrator's privileges and is still in beta test.

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.