He was extradited to the U.S. from Israel in November over the objection of Russian officials. An indictment accused Burkov of running a website called Cardplanet that let people buy stolen credit-card numbers for anywhere from $3 to $60. People used the numbers to make more than $20 million in fraudulent purchases. Prosecutors say Burkov even offered a money-back guarantee if a stolen card number no longer worked.
In court Thursday, Burkov admitted to running a second website on an invite-only basis that allowed cybercriminals to sell stolen data. Israeli officials have suggested Russia sought Burkov's release by offering an exchange for Naama Issachar, a 26-year-old Israeli woman who received a seven-year prison sentence in Moscow on marijuana charges.
Burkov faces a prison sentence of up to 15 years at his May 8 sentencing.