InformationWeek: Security researchers from Kapersky Lab say that the Stuxnet and Duqu viruses shared a common platform that could date back to 2007. The "Tilded" platform could also have been used to create other malware as well. "There were a number of projects involving programs based on the 'Tilded' platform throughout the period 2007-2011," said Kaspersky's Alexander Gostav. "Stuxnet and Duqu are two of them--there could have been others, which for now remain unknown."
Gostav warned that the Tilded platform is likely still under development and could also spawn new malware in the future.