Hector Monsegur "Sabu"

Hector Monsegur was Sabu — the public face and de facto leader of LulzSec, the small splinter crew that broke off from Anonymous in 2011 and spent six weeks taking down Sony Pictures, PBS, the US Senate, the CIA’s public website, and several private security firms in a series of attacks deliberately staged for maximum embarrassment. The FBI identified him from a single instance where he logged into a chat room without his usual Tor protections. They arrested him in June 2011 and turned him within a single overnight session in the New York field office, reportedly by reminding him that his children would enter foster care if he served the sentence he was facing.

For the next nine months, Sabu continued running LulzSec from his apartment with FBI agents in the room. He led his crew into intrusions that the Bureau had already identified, then provided the evidence that put them in court. The arrests of Jeremy Hammond, Mustafa Al-Bassam, Ryan Ackroyd, Donncha O’Cearbhaill and others all flowed through Monsegur’s cooperation. When the cooperation became public in March 2012, the betrayal was treated as one of the foundational events of internet-era informant culture.

He was sentenced to time served plus a year of supervised release in 2014 — a sentence the FBI explicitly argued for, citing his “extraordinarily valuable” cooperation. He has lived publicly since, including under his real name, working as a security consultant. The Sabu cooperation reset the LulzSec / Anonymous wing of the hacking subculture by demonstrating definitively that anonymity is a single-mistake property: one OPSEC failure ends the entire identity.