- The Duqu Framework consists of "C" code compiled with MSVC 2008 using the special options "/O1" and "/Ob1"
- The code was most likely written with a custom extension to C, generally called "OO C"
- The event-driven architecture was developed as a part of the Duqu Framework or its OO C extension
- The C&C code could have been reused from an already existing software project and integrated into the Duqu trojan
All the conclusions above indicate a rather professional team of developers, which appear to be reusing older code written by top "old school" developers. Such techniques are normally seen in professional software and almost never in today's malware. Once again, these indicate that Duqu, just like Stuxnet, is a "one of a kind" piece of malware which stands out like a gem from the large mass of "dumb" malicious program we normally see.