Stuxnet has become the bogeyman of Internt security and cyberwar, showing up in marketing pitches, PowerPoint presentations and press releases from Washington to Silicon Valley to Tehran. But while Stuxnet has been garnering headlines for more than a year now, the far more serious threat in terms of potential long-term damage has turned out to be Duqu. The malware first came to light in September, but it may have been circulating four or five months before that. Its customizable, modular architecture has been a challenge for researchers seeking to understand its operation and its creators' intentions. Threatpost editor Dennis Fisher spoke with Costin Raiu, one of the main researchers working on Duqu at Kaspersky Lab, about the relationship between Stuxnet and Duqu, the possible identity of the attackers and the investigation into its architecture.