Duqu

Duqu is a collection of computer malware discovered on 1 September 2011, thought to be related to the Stuxnet worm. The Laboratory of Cryptography and System Security (CrySyS Lab) of the Budapest University of Technology and Economics in Hungary discovered the threat, analysed the malware, and wrote a 60-page report naming the threat Duqu. Duqu got its name from the prefix "~DQ" it gives to the names of files it creates.

The term Duqu is used in a variety of ways:

Symantec, based on the CrySyS report, continued the analysis of the threat, which it called "nearly identical to Stuxnet, but with a completely different purpose", and published a detailed technical paper on it with a cut-down version of the original lab report as an appendix. Symantec believes that Duqu was created by the same authors as Stuxnet, or that the authors had access to the source code of Stuxnet. The worm, like Stuxnet, has a valid, but abused digital signature, and collects information to prepare for future attacks.Mikko Hyppönen, Chief Research Officer for F-Secure, said that Duqu's kernel driver, JMINET7.SYS, was so similar to Stuxnet's MRXCLS.SYS that F-Secure's back-end system thought it was Stuxnet. Hyppönen further said that the key used to make Duqu's own digital signature (only observed in one case) was stolen from C-Media, located in Taipei, Taiwan. The certificates were due to expire on 2 August 2012 but were revoked on 14 October 2011 according to Symantec.

Another source, Dell SecureWorks, reports that Duqu may not be related to Stuxnet. However, there is considerable and growing evidence that Duqu is closely related to Stuxnet.

Experts compared the similarities and found three of interest:

Like Stuxnet, Duqu attacks Microsoft Windows systems using a zero-day vulnerability. The first-known installer (AKA dropper) file recovered and disclosed by CrySyS Lab uses a Microsoft Word document that exploits the Win32k TrueType font parsing engine and allows execution. The Duqu dropper relates to font embedding, and thus relates to the workaround to restrict access to T2EMBED.DLL, which is a TrueType font parsing engine if the patch released by Microsoft in December 2011 is not yet installed. Microsoft identifier for the threat is MS11-087 (first advisory issued on 13 November 2011).

...
Wikipedia