Credit-card data stolen during a massive data breach at Target last month is hitting the black market, according to multiple reports. Cybersecurity firm Easy Solutions "noticed a 10- to 20-fold increase in the number of high-value stolen cards on black market websites, from nearly every bank and credit union," The New York Times reported. Easy Solutions did not immediately respond to Mashable's request for comment.

Security blogger Brian Krebs, who broke the original story about the Target hack, also reported on Friday that thieves have been selling batches of 1 million cards at "$20 to more than $100 per card."

Krebs reported that a fraud analyst at a major bank told him that "his team had independently confirmed that Target had been breached after buying a huge chunk of the bank’s card accounts from a well-known 'card shop' — an online store advertised in cybercrime forums as a place where thieves can reliably buy stolen credit and debit cards."