Hackers Take Down Visa, MasterCard Websites in Response to their Wikileaks Stance

In an apparent response to MasterCard's refusal to allow customers to donate to whistleblower site Wikileaks, hackers, through coordination on Internet message board 4Chan, apparently managed to take down MasterCard.com this morning through a distributed denial of service attack, technology blogTechcrunch reports.

Other attacks are alleged to have happened against PayPal and PostFinance, a Swiss financial institute, Techcrunch adds, stating that the attacks are in the name of "Operation Payback", an anonymous group that has announced its success on Twitter.

The New York Times confirms the organized attack, and that MasterCard and other sites have recognized the efforts are likely in response to their stance on Wikileaks. As the Times reports:

A spokesman for Mastercard confirmed that the company’s Web site was brought down as a result of "a concentrated effort to flood our corporate Web site with traffic and slow access," but said that card transactions were not compromised. The company, he said, was making concerted efforts to get its site back up, and security teams were working to prevent further outages. The initial decision to deny service to WikiLeaks, he said, was "Mastercard’s alone," and was not made under government pressure.

As of Wednesday afternoon, the Anonymous group on Twitter also claimed it had succeeded in taking down Visa's website as well.