While Frank Janosko was serving time in the Plymouth County Correctional Facility in Massachusetts, he was given access to a computer to conduct legal research.

The computer was a thin client that was only supposed to run the legal database application.

However, by “exploiting an idiosyncrasy in the legal research software,” prosecutors say he found a way to hack into the prison’s network and steal the personal information of more than 1,000 prison employees.

Fortunately, Janosko was caught before any harm was done. He plead guilty to one count of damaging a protected computer, and will serve an extra 18 months in prison as a result, Computerworld reports.

No word on the current status of his computer privileges.