MasterCard's main website was unavailable for some time on Tuesday as it appeared hackers were again targeting the company for its refusal to process donations for the whistle-blowing site WikiLeaks.
MasterCard along with companies such as Visa, PayPal and the Swiss Bank PostFinance stopped processing payments for WikiLeaks shortly after the site began releasing portions of 250,000 secret U.S. diplomatic cables in November 2010.
The hacking collective known as Anonymous spearheaded a drive to conduct distributed denial-of-service (DDOS) attacks against those sites. A DDOS attack involves sending large quantities of meaningless traffic to the website, which can knock it offline.
WikiLeaks wrote on Twitter on Tuesday that "hacktivists" had taken down MasterCard "over the continuing WikiLeaks fiscal embargo." In another Twitter posting, it said the "unlawful banking blockade" was in its sixth month and named Visa, MasterCard, PayPal, Bank of America and Western Union.
A MasterCard spokeswoman in Belgium would not directly answer if the site's downtime was due to a DDOS attack. She said the downtime was due to an "ISP service outage" that affected "multiple users." No cardholder data was affected, as it was MasterCard's corporate, public-facing website.
The MasterCard attacks come as Lulz Security said on Saturday it would stop its hacking campaign. During 50 days of activity, the group exploited weaknesses in a host of corporate and government websites, including the U.S. Central Intelligence Agency, the U.S. Senate, the U.K.'s Serious Organised Crime Agency (SOCA), SonyPictures.com, Fox.com, and most recently the Arizona Department of Public Safety computer network.
A 19-year-old man, Ryan Cleary, was arrested on June 20 at his home in Wickford, Essex, for allegedly taking part in the attacks against SOCA.
He is charged with five computer-related offenses and stands accused of distributing tools to build a botnet used to attack SOCA as well as websites of the International Federation of the Phonographic Industry and the British Phonographic Industry.
In January, U.K. police arrested three teenagers for taking part in DDOS attacks as part of Anonymous. Earlier this month, authorities in Spain said they'd conducted their first police action against Anonymous, arresting three people whom they accuse of directing attack against Sony PlayStation Store, the bank BBVA, the Italian utility company ENEL and websites belonging to the governments of Egypt, Algeria, Libya, Iran, Chile, Colombia and New Zealand.