Duqu is a type of malware that was first discovered in 2011. It is known for its ability to gather intelligence and steal sensitive information from targeted systems. Unlike traditional viruses, Duqu is designed to be stealthy and sophisticated, often using advanced techniques to avoid detection. The malware is believed to be linked to the Stuxnet worm, which was used to disrupt Iran's nuclear program. Duqu primarily targets industrial control systems and has been associated with cyber espionage activities. Its capabilities include keylogging, data exfiltration, and the ability to create backdoors for future access.