June 14, 2021

CrySyS Lab Updates its Duqu Detector Toolkit to Recognize New Variant

(LiveHacking.Com) – CrySyS Lab has updated its Duqu Detector Toolkit to v1.24 to add new signatures for a new variant of the Duqu malware found by Symantec. The classification of the new variant is based on a file Symantec received, however it is only one component of the whole Duqu malware (in this case the loader file that is used to load the rest of the malware when the computer restarts). The file is called mcd9x86.sys and it has a compile date of February 23, 2012. In an attempt to bypass anti-virus software the file has been compiled with different options compared to those used in the previous version. There are also some code changes connected with decrypting the configuration block and loading the malware’s payload.

The Duqu malware has been a topic of constant discussion among security experts since its discovery in October 2011. Recently while analysing its structure, researchers at Kaspersky Lab concluded that the parts of the code which communicate with the command and control (C&C) servers are written in an unknown programming language. Unlike the rest of the Duqu body, it’s not C++ (or Objective C, Java, Python, Ada, Lua). Compared to Stuxnet (which is considered to be a cousin of Duqu and is written completely in C++), this unknown language is one of the defining features of Duqu. Further analysis then revealed that the mystery programming languages was in fact a custom extension to C, generally called “OO C” and that these parts of Duqu were written in “C” code compiled with MSVC 2008 using the special options “/O1” and “/Ob1”

Duqu Detector Toolkit

The detector uses simple signature and heuristic detection techniques to find Duqu infections on a computer or in a whole network. It is able to find traces of infections where components of the malware have already been removed from the system. The Duqu malware got its name because of the temporary files it uses beginning with ~DQ. The detector toolkit also includes a tool to find all Duqu related temporary files on a system.