LulzSec was a group of hackers that gained notoriety for their role in several high-profile computer hacks. The group was founded by a hacker named Sabu, who was later arrested by the FBI and turned into an informant. Most of the members were from the United States, the United Kingdom, Ireland, and other countries around the world. They represent something of a counterpart, though not affiliated, to our list of most prolific Chinese hackers.

The group’s most notorious actions included hacking into Sony Pictures, Fox Broadcasting Company, and News International (the parent company of News Corporation). The group also hacked the U.S. Senate’s website and released thousands of emails from the U.S. Chamber of Commerce. They also hacked PBS, releasing an episode of “Oprah’s Next Chapter” that featured rapper Jay-Z.

LulzSec got caught when one of its members—Sabu—turned to the FBI as an informant after being arrested by them in 2011 for fraud against Visa and MasterCard in retaliation for their refusal to process donations to WikiLeaks during its “Operation Payback” campaign against PayPal for blocking donations to WikiLeaks on behalf of Julian Assange’s arrest warrant in Sweden at Ecuadorian embassy in London due to rape charges filed against him by two women who claimed he sexually assaulted them during their visits there between August 15th – 18th 2010; however, LulzSec was a group of hackers that gained notoriety in 2011 by targeting major websites and government agencies, including the CIA and FBI.

The group’s name is an acronym for “Laughing Out Loud” or “LOL” and “Security.” They were led by Hector Monsegur, who was arrested in 2011 by the FBI and subsequently turned into an informant against other members of LulzSec. His cooperation with law enforcement allowed them to arrest several other members of LulzSec in 2012, who were subsequently sentenced to jail time.

Monsegur’s cooperation with the FBI continues even now, as he assists them with ongoing investigations into cybercrime.

The group’s core members were arrested in 2011, but they continued to operate under new leadership until the group announced its disbanding in 2012. In 2013, Monsegur pleaded guilty to a dozen counts related to his role as an informant for the FBI and was sentenced to time served plus one year of supervised release. He became an informant after he was arrested in June 2011 on hacking charges that could have landed him in prison for up to 124 years had he gone to trial.

In total, LulzSec claimed responsibility for over 100 separate attacks on targets such as Sony Pictures, Fox Broadcasting Company and Nintendo.

LulzSec (or Lulz Security) is a hacking group that was started by members of Anonymous, who wanted to do more than just hack websites, and wanted to actually have fun while doing it.

One of their first targets was the Sony PlayStation Network (PSN), which they hacked on April 20th, 2011. They released names and passwords from the site’s databases, and claimed that over 100 million users had been compromised.

The group continued to attack sites like Fox Broadcasting Company, PBS Newshour, and The Sun newspaper. They also launched an attack against PayPal, where they attempted to steal money from users’ accounts by changing their passwords. They also stole information from AT&T’s servers and posted it online for anyone to see.

The group was eventually caught by police in 2014 when they were raided by officers from Scotland Yard who arrested several members including Jake Davis (aka Topiary), Ryan Ackroyd (aka Kayla), Darren Martyn (aka Pwnsauce), Donncha O’Cearrbhail (aka Palladium), Mustafa Al-Bassam (aka Tflow) and Jeremy Hammond

tl:dr; LulzSec was an online hacking group that gained notoriety for a series of high-profile cyberattacks against organizations, including the Central Intelligence Agency, Sony Pictures, Fox Broadcasting Company, and Nintendo. The group was founded in 2011 by Hector Xavier Monsegur (aka Sabu), with other members coming and going over time.

To better understand LulzSec, here are three good links to explain the group:
1), which provides an overview of the hackers’ activities;

2), which offers more detailed information about their history and operations;

3) . This video explains how LulzSec’s tactics evolved over time and why they were so successful in their attacks against major corporations and government agencies.