Panda Security was targeted for its praise of the arrests of alleged Anonymous members.
Hackers aligned with Anonymous took credit on Wednesday for an attack on Panda Security's website shortly after charges were announced against five of the hacking collective's alleged members.
More than two dozen subdomains within "pandasecurity.com" and other several domains owned by Panda were modified to show a video recounting some of the hacking highlights from Lulz Security or "Lulzsec," a smaller group aligned with Anonymous, according to a post on Pastebin.
Also released were e-mail addresses of people with accounts with Panda, along with their passwords and other internal server details.
Luis Corrons, technical director for the security company's lab, was singled out by the hackers for praising the arrests in a blog post on Tuesday. The hackers accused Panda Security of aiding law enforcement.
On Twitter, Corrons wrote that the company has not helped law enforcement find Lulzsec members but that "I would have loved to be involved in that." He also wrote that "We have our team taking a look into the defacement right now."
The U.S. Attorney's Office for the Southern District of New York on Tuesday announced charges against five people alleged to be involved with Anonymous, Lulzsec and other groups and campaigns that hacked and attacked companies such as Sony Pictures, the analyst group Stratfor Global Intelligence, PayPal and MasterCard.
One of the leaders of Anonymous, Hector Xavier Monsegur -- known by his nickname "Sabu" -- pleaded guilty to a range of hacking charges and faces up to 124 years and six months in prison, according to court documents. Monsegur, who was arrested in June 2011, is said to have helped investigators for months trace Lulzsec and Anonymous participants.