The 20 year old, in his plea agreement, revealed that he joined Lulzsec in the month of May last year in a bid to help the hacking collective carry out cyberattacks on governments and businesses. The hacker, who has been known online through his aliases like “royal”, “wildicv” and “neuron” pleaded guilty at the US District Court for the Central District of California.

Rivera, who surrendered to the FBI on August 28 this year, admitted that he was the one who launched an SQL injection attack against that enabled him to extract confidential information from the website’s database. The plea notes that Sony Pictures incurred losses in tune of $605,663.67 over a year’s time starting May 2011. The expenses were towards hiring computer forensic firms, call centers staffing, etc.

The hacker who was in line for a jail term of 15 years will be recommended for a reduced sentence because of his plea. Rivera’s hearing about the final sentence is scheduled for March 14, 2013.

Members of the disbanded Lulzsec have either gone into hiding or have been arrested. Rivera’s co-conspirator Cody Kretsinger aka “Recursion” pled guilty back in April to one count of conspiracy and one of unauthorized impairment of a protected computer.

Similarly, Hector Xavier Monsegur, who is known to be the leader of the group, was arrested by the FBI in June 2011. Since then Sabu has been work for the FBI as their informant and has led to the arrest of other LulzSec members in and out of the US. Recently he was granted some reprieve in the form of 6-months delay for his sentencing hearing.