Security experts at the US Department of Homeland Security (DHS) fear that variants of the Stuxnet worm could threaten important US infrastructures. In a US House of Representatives committee hearing, Roberta Stempfley and Sean P. McGurk from the DHS's Office of Cyber Security and Communications said that copies of the Stuxnet code have been publicly available for some time, and that the increasing amount of available information about it potentially enables attackers to develop variants that could target a larger number of systems.
According to the two experts, Stuxnet was first discovered in July 2010. It was believed to be targeting an Iranian uranium enrichment facility at Natanz and would only become active once it had identified its target. When asked by anti-virus vendor McAfee in April 2011, 59 per cent of German power, gas and water suppliers replied that they were able to identify the Stuxnet worm in their systems. However, according to the state of knowledge at the time, the worm didn't cause any damage.
Shortly after the discovery of Stuxnet, the DHS started to analyse the code, highly complex according to experts, and inform other governments of its findings. The worm is reportedly intended for industrial control systems that feature a specific hardware and software combination. Stempfley and McGurk said that this type of malware could automatically infect a system, steal sensitive information, manipulate the system and cover up its actions.