MasterCard, Amazon, PayPal are among those in the firing line

Hackers have begun targeting companies that have blocked whistleblowing site Wikileaks from using their services.

The latest target is MasterCard, reported Time. Hackers used distributed denial of service (DDOS) to flood MasterCard’s website with a huge volume of visits, temporarily overloading and shutting down the servers.

The group, calling themselves “Operation: Payback”, has its own website and published a list of the organisations that have hindered Wikileaks in some form. The list currently includes, the French government, EveryDNS and PayPal.

PayPal’s blog was also temporarily disabled by hackers in solidarity with Wikileaks but payment services remained functional, according to CBS News. The online payment service froze its account with Wikileaks on December 3 citing policy violations.

Operation: Payback said they would take action against any website they deemed as “bowing down to government pressure”.

Sources say that despite a high volume of Wikileaks related Tweets the topic was not trending on Twitter, causing speculation that Twitter might also be censoring the discussion. Twitter denies the rumours.

Operation: Payback said on its website: “While we don't have much of an affiliation with WikiLeaks, we fight for the same reasons. We want transparency and we counter censorship. The attempts to silence WikiLeaks are long strides closer to a world where we can not say what we think and are unable to express our opinions and ideas.”

It added: “Wikileaks have been down because of DDOS. There are reasons to believe that the United States Of America are behind this.”

Another group of hackers believed to be in the employ of America, Russia and Britain attacked (and temprarily shut down) the Wikileaks website after it published 250,000 secret diplomatic cables. These latest online attackers appear to be trying to even out the odds on the cyber battlefield.

UPDATE: PayPal has caved into pressure from Wikileaks supporters and reportedly released the whistleblowing websites' funds. More here.

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