Reporting from Washington — A worldwide dispute over WikiLeaks' release of classified information raged online Wednesday like a tale from a comic book: The Jester battled a hacker network calling itself Anonymous that claimed responsibility for taking down the websites of several major corporations.
Anonymous took credit for disabling the main websites for MasterCard and Visa, among several attacks launched against companies that in recent days announced they would no longer handle donations to WikiLeaks.
Cyber attacks also were reported against an attorney representing two Swedish women who have accused WikiLeaks founder Julian Assange of sexual assault, as well as on PostFinance, the financial arm of the Swiss postal system that closed Assange's account after accusing him of providing false information.
Amazon and PayPal also have been targeted.
Meanwhile the Jester has claimed responsibility for taking down WikiLeaks' website several times since it posted its first batch of confidential State Department cables on Nov. 29. The Jester, who describes himself as a patriotic hacker with a military background, claims other like-minded hackers have approached him to help.
Governments around the world have criticized WikiLeaks for releasing classified U.S. documents. WikiLeaks' supporters claim the organization is committed to truth-telling by exposing government secrets. WikiLeaks founder Assange remained in custody in Britain on Wednesday, awaiting a court decision on extradition to Sweden, where he is wanted for questioning on the sexual assault allegations.
Determining exactly who is responsible for the cyber attacks is difficult, given hackers' skill at covering their tracks. But several computer forensics experts said the attacks appeared to be the work of loose networks of vigilantes who are not affiliated with any governments.
About the time Visa.com went down Wednesday, the Anonymous group claimed in a Twitter post that it was responsible for the attack, as part of what it calls "Operation: Payback."
Another post shortly afterward declared: "IT'S DOWN! KEEP FIRING!!!
Taking credit for the MasterCard outages in messages posted over the weekend, the activist group Anonymous brings hackers into secure chat rooms at encrypted websites where potential targets are identified and hackers are encouraged to attack.
Using a concept that law enforcement experts call "leaderless resistance," the members of the volunteer cyber army suggest websites to target but have no defined, accountable leader. In this way, the group has sparked attacks against Kiss bassist Gene Simmons, who spoke out against file sharing, and the Church of Scientology.
Hackers in the Anonymous network say that by denying service to WikiLeaks, companies are in effect asking to be targeted.
"Everyone hit so far has raised their hand and said, 'Can I get in line to be attacked next?'" said Gregg Housh, an activist who has worked on campaigns against Scientology with hackers in the Anonymous network. Housh said he wasn't directly involved in the attacks in defense of WikiLeaks and denied involvement in any illegal activity.
Speaking by phone Wednesday, Housh said one of the Anonymous chat rooms, anonops.net, was under "massive" attack. "It's probably this guy, the Jester," he said.
The Jester, who calls himself a "hacktivist for good," took credit via a Twitter post for disabling WikiLeaks.org last week.
He came to the attention of cyber security experts this year when he disabled several websites run by Islamic extremists. He told computer forensics expert Richard Stiennon in an e-mail in January that he had served in a "rather famous unit" in Afghanistan. The Jester probably served with a non-American NATO force, Stiennon said, and that experience shaped his decision to go after militant websites, and now WikiLeaks.
"He took fire and saw his compatriots killed and that gave him a military trooper view of the world," said Stiennon, based on dozens of emails and chats with The Jester over the past year.
The Jester uses a disruption method that cyber experts had not seen before. The Jester wrote a program called XerXeS that clogs up a website like WikiLeaks.org, instructing it to launch continual requests for information, so the website is too busy to load.
The Anonymous group, like most hackers, shuts down websites by launching what are known as distributed denial of service attacks. Usually, these attacks are launched from a network of thousands of unsuspecting computers connected to the Internet.
Skilled hackers install tiny programs called botnets onto hundreds of thousands of computers that can be activated on command, turning a chain of home desktops and company servers around the world into what hackers call a "zombie army." Those computers, temporarily under the control of the hacker, can direct millions of messages to a single website, overwhelming even the world's biggest servers.
Times staff writers Nathan Olivarez-Giles and David Sarno in Los Angeles contributed to this report.