The London teen behind the massive denial-of-service attack (DDoS) on SpamHaus and Cloudflare has pleaded guilty.

Technology blogger Brian Krebs reported over the weekend that 17-year-old Sean Nolan McDonough, also known by his hacker alias “Narko,” pleaded guilty on Dec. 10 to computer misuse and money laundering in connection with the attack.

McDonough was arrested in September 2013 after he played a role in the March 19, 2013 DDoS attacks aimed at Spamhaus, a Dutch anti-spam group and international nonprofit. SpamHaus later moved its servers behind CloudFlare, which then pushed the attackers to devote their efforts toward the company's network. The attack sent more than 300Gbps of traffic.

The U.K. National Crime Agency told Krebs that, “court reporting restrictions are in place in respect to a juvenile offender, [and] as a consequence the NCA will not be releasing further detail.”

[An earlier version of this article incorrectly said the attack reached 85Gbps.]