ST. PAUL — A northern Minnesota man admitted Tuesday to a “cryptojacking” scheme that cost his former employer more than $45,000.

Joshua Paul Armbrust, 44, of Orr, pleaded guilty to a charge of computer fraud at a hearing in U.S. District Court.

Armbrust was employed by Digital River, a Minnetonka-based global e-commerce and payment processing company, until his resignation in February 2020. However, he reportedly continued to use their resources for personal gain for more than a year after his departure.

Cryptojacking is a form of cybercrime where an unauthorized party uses someone else’s computing resources to mine cryptocurrency, such as Bitcoin or Ethereum, by accessing the victim’s hardware.

This unauthorized use can reduce system performance and drive up energy consumption, resulting in significantly higher operating costs.

Court documents indicate Armbrust
remotely accessed Digital River’s Amazon Web Services account
on multiple occasions without authorization between December 2020 and May 2021 to mine Ethereum at the expense of his former employer.

The cryptocurrency was then directed into a digital wallet and subsequently transferred to two Coinbase accounts registered solely in Armbrust’s name. Prosecutors said Armbrust then liquidated the mined Ethereum, totaling over $7,000, and transferred the proceeds to his bank account.

Armbrust was indicted by a federal grand jury in October and was briefly jailed as a result of the FBI investigation. He was released under supervision after making an initial court appearance in November.

Judge Jerry Blackwell on Tuesday allowed Armbrust to remain free under his previous bond pending sentencing, which was not immediately scheduled. The charge, as listed in the indictment, carries a maximum sentence of five years in prison.

Digital River, which was founded in 1994, announced in January that it was
shutting down and laying off 122 people
employed through its Minnesota headquarters.