A "cyber event" interrupted grid operations in parts of the western United States in early March, but the hack was just disclosed to the public a few days ago.
The attack marked a somber milestone for the US power sector: the unnamed utility company is the first to report a malicious event that disrupted grid operations.
"According to a cryptic report posted by the Department of Energy, the March 5 incident lasted from 9 a.m. until nearly 7 p.m. but didn't lead to a power outage, based on a brief summary of the electric disturbance report filed by the victim utility," E&E News reported on April 30.
Authorities don't know the source of the cyber event.
E&E News posted an update today, which includes the following information:
The hack itself occurred two months ago, on March 5, when a "denial-of-service" attack disabled Cisco Adaptive Security Appliance devices ringing power grid control systems in Utah, Wyoming and California, according to multiple sources and a vague summary of a Department of Energy filing.
There were no blackouts, no harm to power generation and evidently very little effect on the Western transmission grid, according to multiple sources and officials. The most direct impact was likely a temporary loss of visibility to certain parts of the utility's supervisory control and data acquisition (SCADA) system, though all major transmission operators in the regions affected denied having been hit by the denial-of-service attack. (source)