The websites of MasterCard and the office of Joe Lieberman have been the latest websites to be taken down due to a distributed denial-of-service (DDoS) attack.
Lieberman, chairman of the US Senate's committee on homeland security, announced last week that he had contacted Amazon about its hosting of the WikiLeaks website, which was halted 24 hours later.
Meanwhile a report from CNET claimed that MasterCard was pulling the plug on payments to WikiLeaks, meaning that the only easy way to donate electronically would be with a Visa credit card through a web page hosted by Iceland-based DataCell.com.
However these actions have led to both sites being hit by DDoS attacks over the last 24 hours as part of the Anonymous group's ‘Operation Payback' effort, which is taking a temporary break from the efforts against the entertainment industry in order to spend some time helping WikiLeaks by taking down its increasing opponents.
On its Twitter feed, Anonymous said an hour ago that MasterCard was down claiming that the ‘group that took down Swiss bank site has now taken down MasterCard.com'.
Sean-Paul Correll, threat researcher and security evangelist at Panda Security, who has been tracking the actions of the attacks, commented that MasterCard.com first went down at 9:14am GMT today with four service interruptions.
Alan Bentley, SVP international of Lumension, commented that the attack on MasterCard's website, following its move to block payments to WikiLeaks, certainly should not surprise anyone.
“Many disgruntled 'hacktivists' will be seeking revenge on behalf of the whistle-blowing website and it is highly likely that this will be the first in a series of attacks on businesses such as Amazon, PayPal, Visa and Swiss Bank, all of which withdrew services to WikiLeaks over recent days,” he said.
“The WikiLeaks saga is undoubtedly set to continue for some time and all organisations involved will want to beef up their security efforts in a bid to protect themselves from the wrath of the hacktivist community."
With regards to the attack on the Lieberman website, Correll commented that this was the first hit on a US government website and caused eight service interruptions with 12 minutes of downtime.
Among the other sites to be hit were advbyra.se, the lawyer of the two girls who were allegedly assaulted by WikiLeaks founder Julian Assange, who is now being held in custody in London. Also, a small group of Anonymous protesters started to attack Sarah Palin's website (sarahpac.com) in retaliation for saying that Assange should be hunted like a terrorist.
Correll said: “We have observed 256 service interruptions and 94 hours of combined downtime since these attacks started on 4th December. We also observed over eight hours of counter-DDoS downtime on the attackers (anonops.net) site.”
The Anonymous group confirmed the counterattacks initially on Monday evening when it said it was ‘currently under heavy DDoS attack', with just under two hours of downtime and 23 service interruptions recorded since the pro-WikiLeaks attacks started that morning.
In an update last night, it said that Operation Payback has been under a constant DDoS counterattack, but the attacks against the site had intensified shortly after announcing the attack on Lieberman's website.
Correll said that he was not sure who exactly was involved in the retaliation against the group, but suspected that it may be a group of patriots attempting to protect the greater interests of the United States of America.
Using the Twitter handle ‘th3j35t3r', it previously took down the WikiLeaks website at the end of November ‘for attempting to endanger the lives of our troops, ‘other assets' and foreign relations'.