A US power company was shut down for three weeks by a virus brought in by an infected USB stick.
According to media reports, a US Department of Homeland Security report did not identify the plant but said that the virus was introduced last October by an employee of a third-party contractor that does business with the utility, according to Reuters.
The US Department of Homeland Security's Industrial Control Systems Cyber Emergence Response Team (ICS-CERT), which helps protect critical US infrastructure, described the incident in a quarterly newsletter that was accessed via its website on Wednesday.
It also described a second incident, in which the Cert said it had recently sent technicians to clean up computers infected by common as well as ‘sophisticated' viruses on workstations that were critical to the operations of a power generation facility. According to USA Today, that was at another plant, where government computer experts discovered ‘common and sophisticated malware' on several workstations, including two that were critical to the plant's operation.
ICS-CERT said that it responded to 198 cyber incidents reported by energy companies, public water districts and other infrastructure facilities in the fiscal year ending 30th September 2012. Its report said: “ICS-CERT's onsite discussions with company personnel revealed a handful of machines that likely had contact with the tainted USB drive. These machines were examined immediately and drive images were taken for in-depth analysis.
“ICS-CERT also performed preliminary onsite analysis of those machines and discovered signs of the sophisticated malware on two engineering workstations, both critical to the operation of the control environment. Detailed analysis was conducted as these workstations had no backups, and an ineffective or failed clean-up would have significantly impaired their operations.”