Hackers knock some U.S. airport websites offline

Airports in Los Angeles and Atlanta were among those affected. Officials say there was no effect on operations

Websites for a handful of U.S. airports, including those in Atlanta, Chicago, New York and Los Angeles, were taken offline during a cyberattack Monday, although officials said there was no effect on flight operations.

Managers at multiple airports said they notified the FBI and the Transportation Security Administration about the cyberattacks. In a statement, the FBI said it was aware of the incident but had no additional information. The TSA declined to comment, referring inquiries to individual airports.

The attacks were carried out by a group of pro-Russian hackers known as Killnet, according to John Hultquist, vice president for intelligence at Mandiant, an American cybersecurity firm. Killnet called for coordinated denial-of-service attacks on cyber targets from a list it posted on its Telegram channel — a list that included several major U.S. airports. Denial-of-service attacks occur when a target is flooded with traffic until it can’t respond or crashes.