US Power Grid Cyberattack Due to Unpatched Firewall: NERC

The North American Electric Reliability Corporation (NERC) reports that a cyberattack on the US power grid earlier this year was caused by a target entity's network perimeter firewall flaw.

On March 5, 2019, an incident targeted a "low-impact" grid control center and small power generation sites in the western US, according to an E&E News update. No signal outages lasted longer than five minutes, and the disruption didn't cause any blackouts. Still, the 10-hour attack was great enough to prompt the victim utility to contact the US Department of Energy.

A "Lesson Learned" post from NERC says attackers exploited a vulnerability in the web interface of a vendor firewall, enabling attackers to repeatedly reboot the devices and cause a denial-of-service condition. The unexpected reboots let to communication outages in firewalls that controlled communication between the control center and multiple remote generation sites, and between equipment on these sites. All firewalls were network perimeter devices.

Analysis revealed the target utility hadn't installed a firmware update that would have patched the vulnerability, and the outages stopped when the patch was applied. The victim reviewed its process for assessing and implementing firmware updates and has chosen to implement a more formal, frequent review of vendor updates monitored by internal compliance tracking software.

Read more details here.

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