Now it's cyber war: Army of hackers target MasterCard and PayPal in revenge of WikiLeaks

1. Visa, PayPal, Amazon also come under attack 
2. Card unable to make online payments for six hours
3. 5,000 'hacktivists' believed to be behind this

Computer hackers have sent two of the world’s biggest credit card companies into meltdown in revenge for cutting off payments to the WikiLeaks website.

The attack was launched by a shadowy international group called ‘Anonymous’ which said MasterCard and Visa had been targeted for freezing the account of the whistleblowing site.

The devastating blow to the credit card giants came on one of the busiest online shopping days of the year.

Hackers also targeted online payment system PayPal, Amazon and a Swiss bank over the WikiLeaks row.

Yesterday, a six-hour stoppage on the Mastercard secure code system is thought to have affected hundreds of thousands of shoppers worldwide and highlights how vulnerable the world’s computer systems are to attack.

Last night Visa website was also taken down for a period after it came under attack.

It is thought just a few dozen ‘hacktivists’ launched the electronic onslaught, which was taken up by other supporters.

Operation: Payback was formed in September to target groups opposed to internet piracy

The ‘distributed denial of service’ (DDoS) attack involved around 2,000 computers bombarding the website’s host computers with requests for information, causing them to crash.

WikiLeaks has been publishing classified U.S. diplomatic cables, to the fury of Washington authorities.