A US man pleaded guilty in federal court in San Diego admitting that he carried out a series of denial-of-service (DoS) computer hacking attacks against multiple victims between 2013 and 2014.

A denial-of-service (DoS) attack occurs when legitimate users are unable to access information systems, devices, or other network resources due to the actions of a malicious cyber threat actor. In such attacks, the hacker floods the targeted host or network with traffic until the target cannot respond or simply crashes, preventing access for legitimate purposes.

Between December 2013 and January 2014, Austin Thompson attacked online gaming companies and servers, including then San Diego-based Sony Online Entertainment. Thompson flooded his victims’ servers with enough internet traffic to take them offline. The attacks took down game servers and related computers around the world, often for hours at a time. According to the plea agreement, Thompson’s actions caused at least $95,000 in damages.

Thompson used the Twitter account @DerpTrolling to announce that an attack was imminent and then posted screenshots or other photos showing that victims’ servers had been taken down after the attack.

The case, which is being prosecuted by Assistant U.S. Attorneys Benjamin Katz and John Parmley, arose out of an investigation by FBI’s San Diego Field Office.

Thompson is due to be sentenced at a hearing before United States District Judge Jeffrey Mille on 1 March, 2019. The maximum sentence for the crimes is 10 years in jail and fines of up to $250,000.