According to a Reuters news report, Gonzalez faces 17 to 25 years in jail as a result of his plea. Sentencing is due to take place in March.
The hacks of Heartland and TJX alone compromised more than 220 million customer credit card records, according to industry statistics, making them the two largest known breaches in Internet history.
While the breaches at Heartland, Hannaford, and 7-Eleven were well-publicized, the data loss at Target had not been previously revealed. Target spokeswoman Amy Reilly told Reuters that her company had an "extremely limited" number of payment card numbers stolen by Gonzalez about two years ago.
She declined to tell Reuters how many card numbers had been stolen, and described the term of the exposure as brief. "We believe that, at most, only a tiny fraction of guest credit and debit card data used at our stores may have been involved," she said.
Reilly told Reuters that Target had notified the card issuers about the breach, leaving them to tell their customers.
In his plea, Gonzalez told the judge he had abused many forms of drugs and alcohol. His lawyers argued that substance abuse was part of the reason for his actions, according to the news report. A psychiatrist hired by Gonzalez also stated he has symptoms consistent with Asperger's syndrome, the same defense used by accused mega-hacker Gary McKinnon in the U.K.
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