The Homeland Security's Industrial Control Systems Cyber Emergency Response Team, ICS-CERT, has issued a warning saying natural gas pipelines are under cyber attack and have been so since December 2011.
ICS-CERT, which is based in Idaho, said that several gas pipeline companies have been enduring a sustained attack on their networks by the same sources.
DHS has asked utilities to not remove any malware or patch security holes if they don't jeopardize safe operations, according to people who have seen the alerts. One said that the details of the threats and the frequency of alerts "indicated to me this was pretty serious."
DHS also said the attacks begin with spam-phishing email scams sent to gas pipeline employees and is working with the FBI to further investigate.