PayPal's website was hit late Wednesday by two botnets as online activists continued their Web attacks on companies that have severed their relationships with WikiLeaks.
Also watch: The worst moments in network security history
The activists have recruited volunteers, who have banded their computers into a distributed denial of service (DDoS) botnet, but they are also using hacked machines to carry out these attacks, said Sean-Paul Correll of threat researcher Panda Security. "Today we observed over 3,000 computers in the voluntary botnet, but we also have knowledge of a 30k node botnet," he said.
This botnet infects computers via peer to peer filesharing systems, but it can spread via Microsoft Messenger and USB sticks as well, he said. Panda is trying to get a sample of the botnet code to analyze.
PayPal was hit late Wednesday afternoon, Pacific time, and the Paypal.com address was unresponsive into early Thursday morning. "There have been attempted DDoS attacks on paypal.com this week," said company spokesman Anuj Nayar. "The attacks slowed the website itself down for a short while, but did not significantly impact payments."
PayPal's blog had been hit earlier in the week, but the main Paypal.com Web site was down for at least several hours Wednesday, and www.paypal.com was affected too, although less seriously. Unlike Visa and MasterCard, the website is critical to PayPal's business. Customers need the Web site to send money to other PayPal users.
Paypal wasn't the only company to have some payments affected, however. MasterCard's SecureCode service -- used to add a security code for use in online transactions, similar to a PIN (personal identification number), also suffered a disruption Wednesday, said MasterCard spokesman James Issokson. "There were some operational issues and they have been resolved," he said.
Representatives of the Anonymous group's Operation Payback said that they were responsible for this disruption. They believe that MasterCard's Web servers may have shared resources with the SecureCode system. In a MasterCard advisory,published on the Securetrading blog, MasterCard said that a directory server had failed.
Both MasterCard and Visa also had their public websites knocked offline by a "hive" of as many as 3,000 activists who had downloaded Web-attacking software, which was then turned on different Web sites.
For several months now, Operation Payback has gone after Web sites belonging to organizations that have cracked down on unlicensed music and movie copying -- the Motion Picture Association of America (MPAA) and the Recording Industry Association of America (RIAA). This week, the project took up cyber arms against companies that have cut business ties with WikiLeaks, making it harder for the website to raise money and continue operations. They have also hit Web sites belonging to WikiLeaks critics such as U.S. Sen. Joseph Lieberman and former Alaska Gov. Sarah Palin.
For Operation Payback, attacks on WikiLeaks are attacks on free speech.
"We are really just a collection of people from all walks of life, all over the world who are sick of watching people being exploited by outdated and vague copyright/freedom laws," said one group member who used the name Emily in an online chat.
The attacks will continue until those laws are reformed, Emily said.
But the operation has had some trouble of its own. Facebook and Twitter have closed accounts used by the group, and its Web site was offline Wednesday as well. Replacement accounts such as this Twitter page soon sprang up, however.
Learn more about this topic
This story, "Group used 30,000-node botnet in MasterCard, PayPal attacks" was originally published by IDG News Service .