Duqu: Protect Your Private Keys

Some of the files associated with the new W32.Duqu threat were signed with a private key. After intense investigation we concluded that the private key used for signing these Duqu files was stolen from a Symantec customer whose systems appear to have been compromised. The private key was associated with a code signing certificate issued to that customer.

via symantec.com

Symantec have commented on the W32.Duqu threat