An anonymous reader writes "The sections responsible for downloading and executing additional modules in the Duqu Trojan, referred to by some as Stuxnet 2.0, were written in standard C++. A big chunk of it, the payload DLL, which communicates exclusively with the Command and Control (C&C) server so that the worm knows what to do once it has infected a system, has object-oriented code that doesn’t resemble anything seen before. Security researchers worked out what the mystery code does, but because they weren’t sure about the syntax, they asked the community for help in identifying the programming language. Over a week later, it turns out the Duqu Framework was written in C code, which was then compiled with MSVC 2008 and options
/O1 (minimize size) /Ob1 (expand only __inline)."