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