U.S. security officials say that the country's natural gas pipeline operators have been targeted in a series of cyber attacks over the last several months.
The country's Homeland Security agency said Tuesday the attacks involve “sophisticated spear-phishing” — fake emails that appear to be legitimate to employees at the natural gas companies –designed to try to get them to divulge passwords or other secure information.
Homeland Security has issued several warnings to the companies, which supply about a quarter of the country's energy needs. It is unclear who might be behind the cyber attacks.
The fraudulent emails may date to last December. While it continues its investigation, the agency has asked that the companies not remove evidence of the attacks from their computers if it does not jeopardize safe pipeline operations.