U.S. authorities have seized 13 extra domains linked to among the world’s hottest DDoS-for-hire web sites.

These web sites, additionally described as “booter” or “stressor” providers, are marketed as professional safety testing instruments that permit admins to stress-test web sites. In actuality, the providers are used for launching denial-of-service (DDoS) assaults designed to overwhelm web sites and networks and pressure them offline.

The DOJ introduced on Monday that the FBI had seized 13 extra domains linked to among the most prolific booter providers as a part of Operation PowerOFF, a global legislation enforcement effort to disrupt on-line platforms that permit anybody to launch large distributed DDoS assaults.

Nonetheless, the Justice Division mentioned that 10 of the 13 domains seized by legislation enforcement this week have been linked to earlier domains seized in a December 2022 sweep that took down 48 booter providers.

“For instance, one of many domains seized this week – cyberstress.org – seems to be the identical service operated beneath the area cyberstress.us, which was seized in December,” the DOJ mentioned. “Whereas most of the beforehand disrupted booter providers haven’t returned, at the moment’s motion displays legislation enforcement’s dedication to focusing on these operators who’ve chosen to proceed their felony actions.”

TechCrunch visited the 13 web sites seized by the FBI this week. Whereas nearly the entire web sites focused by the operation now show a message stating they’ve been seized by the FBI, TechCrunch discovered that — on the time of writing — not less than one of many websites continues to function as regular. It’s not clear why this website continues to load and the DOJ has but to answer TechCrunch’s questions. 

As a part of its investigation into the domains, which the DOJ says have “a whole lot of hundreds” of registered customers and have been used to focus on college districts and authorities web sites, the FBI opened or renewed accounts with every service after which examined them by launching DDoS assaults in opposition to government-controlled computer systems. It then noticed the impact on these “sufferer” computer systems. 

“In some instances, regardless of the ‘sufferer’ pc being on a community with a considerable amount of capability, the take a look at assault was so highly effective that it utterly severed the web connection,” the DOJ mentioned. 

The Justice Division additionally mentioned in Monday’s announcement that 4 of the defendants charged in December — Jeremiah Sam Evans Miller, Angel Handbook Colon Jr, Shamar Shattock and Cory Anthony Palmer — pleaded responsible earlier this 12 months. These defendants, who’re scheduled to be sentenced this summer time, have been linked to the operation of the now-defunct “RoyalStresser.com”, “SecurityTeam.io”, “Astrostress.com”, and “Booter.sx” DDoS-for-hire providers. 

The takedowns have been carried out as a part of a joint operation between the U.Ok.’s Nationwide Crime Company, Dutch police and Europol. Earlier this 12 months, the NCA introduced it had infiltrated the web felony market by organising various websites purporting to supply DDoS-for-hire providers.