(Reuters) - The arrests of six suspected leaders of the loose-knit international hacking group Anonymous comes after a long string of cyber vandalism against major companies and government agencies around the world.
Dec 2010: Anonymous' early attacks took aim at the websites of Mastercard, Visa and eBay's PayPal in retaliation for the companies' refusal to accept donations for Wikileaks, whose founder was in legal hot water for publishing confidential diplomatic cables.
Early 2011: Anonymous, along with its affiliates such as Lulz Security or LulzSec, hacked the websites of the governments of Tunisia, Algeria and Zimbabwe. Tunisia was then part of the Arab Spring while Algeria has been largely untouched by the unrest. Zimbabwe has been governed by Robert Mugabe since independence in 1980. (Lulz is Internet slang for laughs)
February 2011: Anonymous hackers broke into the network of HBGary after an executive said he had learned the identities of the group's leaders.
May 2011: Lulz, angered by a PBS documentary about WikiLeaks, posted a fake news story on the PBS website claiming that dead rapper Tupac Shakur is alive and well. It also claimed credit for breaking into Fox.com and publishing data about contestants for a Fox show "X Factor." Fox is a unit of News Corp.
June 2011: Lulz hackers broke into Sony Corp's computer systems to demonstrate that the company had shoddy security. They also hacked into Nintendo but the incident does not appear to have serious consequences.
Lulz also breached one of the U.S. Senate's computer network but did not appear to get access to sensitive data. It also took down the public website of the U.S. Central Intelligence Agency with what appeared to be a denial of service attack, where hackers inundate a website to crash it.
Lulz knocked offline a website run by the British police Serious Organised Crime Agency, which targets organized crime. Lulz also struck an Arizona police website to show opposition to a tough anti-immigration law.
June 21: British police arrest a 19-year-old man, Jake Davis, in eastern England. Suspects were also picked up in the United States, Spain, Turkey and the Netherlands. Davis was known on Twitter as topiary, describing himself as a "simple prankster turned swank garden hedge."
June 22: Hackers briefly disabled three websites belonging to Brazil's government. The sites for Brazil's federal government, presidency, and tax collection agency were inaccessible to the public for about two and a half hours overnight but their operation was quickly restored.
June 25: Lulz Security announced it is disbanding, although the original group, Anonymous, will press on.
It was also in June that Hector Xavier Monsegur, the hacker known as Sabu, was arrested at his small Manhattan apartment. He secretly pleaded guilty to 12 charges in August, and began cooperating with authorities.
July 4: Anonymous said it broke into an Apple Inc server and published a small number of usernames and passwords for one of the company's websites.
July 11: Anonymous hackers said on Twitter that they broke into the computer systems of major government contractor Booz Allen Hamilton. The hackers said that they wiped out 4 gigabytes of source code and stole 90,000 email addresses.
December 2011: Antisec hackers, who are also tied to Anonymous, broke into Stratfor Global Intelligence Service, stealing data like client list details on 90,000 credit card accounts.
January 2012: Hackers broke into the personal email of an Irish police officer, and use information learned there to listen into a law enforcement conference call. They post it online.
March 2012: Police announce charges against six hackers associated with the Anonymous groups, including Monsegur.
(Reporting By Diane Bartz)