Mastercard has become the latest victim of hacktivist group ‘Anonymous’, which today launched potent DDoS attacks against the company’s main websites, including the .com address and other European sub-sites.

The attack is part of the group’s ongoing ‘operation payback’ against organisations that have withdrawn support in various ways for the beleagured Wikileaks website. As of 1pm GMT, the sites were still unavailable even as the group appeared to boast of its hit on Twitter.

Mastercard joins a lengthening list of websites downed by the group this year, which is rapidly turning into the best-known political hacktivist group on the Internet. Victims in the last week include Swiss bank, PostFinance and Net payments provider, PayPal, both also attacked in symbolic aid of Wikileaks and its imprisoned head Julian Assange.

Rock legend Gene Simmons has also had a bad year at the group’s hands after making comments against the group, which started life attacking organisations that support or enforce music copyright. The group is also known to be hostile to the Church of Scientology.

“First, they will be punished. Second, they might find their little butts in jail, right next to someone who’s been there for years and is looking for a new girlfriend,” said Simmons on his website of the group, a prediction that looks as far away from coming true as ever.  

On the contrary, the group seems able to mount DDoS strikes almost at will using what in Internet terms count as small botnets.

Separately, the firm that makes possible donations to Wikileaks, Datacell, has said it plans to sue the companies after they stopped payments to Wikileaks through their networks.