The FBI executed 40 search warrants across the country Jan. 27 as part of an ongoing investigation into distributed denial-of-service attacks launched in "Operation Payback."
The raids came the same day U.K. authoritiesarrested five people believed to be tied to the loosely affiliated group Anonymous, which has taken credit for the attacks. The suspects in the U.K. range in age from 15 to 26, and were picked up after being tied to the attacks.
The goal of Operation Payback was to retaliate against companies or institutions that cut ties to WikiLeaks or were viewed as enemies of the whistle-blower site. The effort impacted a number of high-profile companies, including PayPal and MasterCard, as well as targets such as the Swedish prosecutor's office and PostFinance, a financial institution in Switzerland that closed an account belonging to WikiLeaks founder Julian Assange.
Besides the U.K., authorities in the Netherlands have made arrests in the case as well.
Hacktivists have increasingly turned to denial-of-service attacks as a method of protest, while others have used them as a way to silence critics. A report last year from Harvard University's Berkman Center for Internet & Society found 280 independent media and human rights Websites had been hit by 140 attacks between September 2009 and August 2010. Since 1998, the researchers counted reports of 329 different attacks against more than 815 sites-numbers they estimate are only a small portion of actual attacks.
The FBI said it is working closely with other law enforcement agencies across the globe, and said major antivirus companies have updated their software to detect the Low Orbit Ion Cannon tool used in the attacks.
"The FBI also is reminding the public that facilitating or conducting a DDoS attack is illegal, punishable by up to 10 years in prison, as well as exposing participants to significant civil liability," the agency said in a press release.