The swoop on Thursday was part of an international police operation that included the UK Metropolitan Police Central eCrime Unit (PCeU), the FBI said. It follows the arrest of five young men in the UK on suspicion of involvement in the same Operation Payback series of distributed denial-of-service attacks (DDoS).
Anonymous's Operation Payback took down sites like visa.com after the company stopped accepting Wikileaks' payments. Credit: Elinor Mills/CNET News
The Anonymous group of online activists has claimed responsibility for a series of successful attacks against websites belonging to businesses including Visa, MasterCard and PayPal, which stopped processing payments destined for Wikileaks.
The five men arrested in the UK have been granted police bail, the Met said in a statement on Friday. The three youngest — who are aged 15, 16 and 19 years old — must report to police on 13 April, while the oldest two — aged 20 and 26 — must report on 14 April.
French authorities were also involved, according to the FBI.
Antivirus companies have put out updates to detect the Low Orbit Ion Canon (LOIC) tool thought to have been used in the attacks, the FBI said, adding that the US's National Cyber-Forensics and Training Alliance is helping in the investigation.