The rocker, by the name of Geoffrey Commander, used to play on big stages
He was not alone, 12 others were in the same position.
The reason for the legal trouble was that he contributed to the amplification of the attack by using the LOIC (low-orbit Ion cannon) tool along with thousand others, in a form of protest.
LOIC is a network stress test, specifically for running DDoS attacks by flooding the target server with bad traffic; the larger the number of participants, the more crippling the attack is for the target.
Rocker promises to never return to the US again, which should be in less than ten days after sentencing on late Friday, Washington Times reports. Initially, Commander faced 10 years of jail time in a federal prison, but the charges brought against him were afterwards downgraded to a misdemeanor.
Basically, what the guitarist did in 2010 was to enter an IRC chat room administered by members of Anonymous hacker collective and join the 1,000 individuals who were already involved in an attack that marked MasterCard as the victim. It seems that the company recorded a loss of $1 million / €800,000 as a result of the incident.
He took part in the attack for three hours and then he quit. He was arrested last year, after getting back to the US from England with his family, years after the attack.