The forces of Anonymous have taken aim at several companies who are refusing to do business with WikiLeaks. 4chan's hordes have launched distributed denial-of-service attacks against PayPal, Swiss bank PostFinance, and other sites that have hindered the whistleblowing site's operations.

A self-styled spokesman for the group calling himself "Coldblood" has said that any website that's "bowing down to government pressure" is a target. PayPal ceased processing donations to the site, and PostFinance froze WikiLeaks founder Julian Assange's account. The attacks are being performed under the Operation: Payback banner; Operation: Payback is the name the group is using in its long-running attacks on the RIAA, MPAA, and other organizations involved with anti-piracy lawsuits.

The initial attacks against PayPal were substantially ineffective; the PayPal blog was taken offline, but the main PayPal site wasn't harmed. The attacks against PostFinance, however, have resulted in the bank's website being unavailable for more than 16 hours. It remains unavailable at the time of writing. The latest target is the site of the Swedish prosecutors in Assange's sexual misconduct trial. This too appears to be offline. Twitter has also been named as a future attack target, due to its claimed censorship of the #wikileaks hashtag.

The companies being attacked deny that their behavior is a result of government influence. Rather, they are claiming that WikiLeaks and Assange have failed to adhere to the terms of use of various services. Amazon, which for a time hosted the site, said that WikiLeaks was failing to ensure that it "wasn't putting innocent people in jeopardy." PostFinance said that Assange lied on an application form.

In a case of tit-for-tat, unknown forces have since launched a denial of service attack against Anonymous' own site (one that took it offline shortly after publication), though the IRC channel used for coordination is still operational, and its denial-of-service software, LOIC, is still functioning properly.

WikiLeaks was itself the target of massive denial of service attacks in the wake of its release of thousands of US embassy cables. The source of these attacks remains unknown. In addition to making the main WikiLeaks site hard to access, DoS attacks against DNS provider EveryDNS resulted in the company cutting WikiLeaks off, as it was unwilling to tolerate the excess traffic.

In spite of this, hundreds of mirrors of the site have popped up across the globe, with Anonymous claiming to have created many of them. An "insurance file"—an encrypted torrent of the entire cable dump—has been widely distributed, along with the promise that the decryption key will be published should anything bad happen to WikiLeaks.

Assange himself is currently remanded in custody in the UK. Swedish prosecutors are seeking to have him extradited to face sexual misconduct charges. He surrendered to police in London and was arrested. Bail was refused over fears that he might flee, and also due to some fear that he was at risk from "unstable persons." With widespread calls for his murder, this might not be too far-fetched.