Officials from San Diego County and Hewlett-Packard (NYSE: HPQ) are investigating what appears to have been a deliberate attempt to breach the county's main public-facing website during the election Tuesday night.
The disturbance did not affect ballot counting or other election processing, according to county officials, but limited public access to voting results during a peak traffic period.
It is not clear whether the attempted breach was aimed at interfering with the election.
The disruption began at about 8:15 p.m., when the county's IT system detected an abnormal surge in online traffic to sdcounty.ca.gov from a single, unknown IP address. The number of hits from that account rapidly jumped to significantly more than 1 million per minute.
The county's firewall recognized it as suspicious activity and closed off outside access to all of the county's websites for security purposes.
The event disrupted public access to the Registrar of Voters' website, sdvote.com, as election results were being posted, and blocked access to all other external county sites until 9:56 p.m. Tuesday. Internally, all sites continued to function, and county employees were still able to provide election information through paper copies.
Hewlett-Packard, which provides IT services to the county, called the event a "denial-of-service attack," which is when an "attacker attempts to prevent legitimate users from accessing information services," according to the U.S. Department of Homeland Security's Computer Emergency Readiness Team.
Hewlett-Packard officials ruled out any technical, hardware or software failure and determined the county's websites did not crash or fail. The county's internal security system worked properly and blocked any additional threats.