An admitted computer hacker who helped the FBI thwart hundreds of cyberattacks on government and corporate computer systems will be freed from prison.
Hector Xavier Monsegur was sentenced yesterday in Manhattan to the time he had already served - seven months.
Monsegur infiltrated the servers of major corporations but switched sides and helped the US government disrupt hundreds of cyberattacks on Congress, Nasa and other sensitive targets, according to federal prosecutors.
New York prosecutors detailed the cooperation of Monsegur in court papers while asking a judge to reward him with leniency at his sentencing. They credited Monsegur with helping them cripple Anonymous, the notorious crew of hacktivists who stole confidential information, defaced websites and temporarily put some victims out of business.
Working around the clock with FBI agents at his side, Monsegur "provided, in real time, information about then-ongoing computer hacks and vulnerabilities in significant computer systems", prosecutors wrote. The FBI estimates he helped detect at least 300 separate hacks, preventing millions of dollars in losses.
Court papers say Monsegur first began hacking in a Manhattan apartment in the early 2000s. His aim then was to steal credit card information, then sell it or use it to pay his own bills.
In a 2011 interview, Monsegur said he decided to join forces with Anonymous because he was upset over the arrest of WikiLeaks founder Julian Assange.
"I'm just doing what I know how to do, and that is counter abuse," he said.
Starting in early 2011 and using the alias Sabu, Monsegur led an Anonymous splinter group called Lulz Security, or LulzSec, which hacked computer systems of Fox television, Nintendo, PayPal and other businesses, stole private information and then bragged about it online. The group was loosely affiliated with Jeremy Hammond, the FBI's most wanted cybercriminal whose stated objective was to cause mayhem with the attacks, prosecutors said. Hammond was sentenced last year to 10 years in prison.
When FBI agents showed up at his home in the summer of 2011, Monsegur immediately agreed to cooperate, giving the FBI a tutorial on the inner workings and participants of LulzSec and Anonymous, prosecutors said. Under their direction, he "convinced LulzSec members to provide him digital evidence of the hacking activities".
Reports that Monsegur was cooperating made him a pariah in the Anonymous movement, prosecutors said. Hackers began posting personal information about him, and he was threatened. He and family members had to be relocated by the FBI.