Kaspersky Lab has been analysing the infamous duqu worm code for several months. In one of the latest writeups, Igor Soumenkov describes part of Duqu code – for which there is an open debate around what language was used for its development. The discussion is quite interesting so I compiled a list of the relevant write-ups in chronological order:

Duqu FAQ
The Mystery of Duqu: Part One
The Mystery of Duqu: Part Two
The Mystery of Duqu: Part Three
The Duqu Saga Continues: Enter Mr. B. Jason and TV’s Dexter (this is considered as part 4)
The Mystery of Duqu: Part Five
The Mystery of Duqu: Part Six (The Command and Control servers)
Stuxnet/Duqu: The Evolution of Drivers