“PoSeidon,” a new strain of malicious software designed to steal credit and debit card data from hacked point-of-sale (POS) devices, has been implicated in a number of recent breaches involving companies that provide POS services primarily to restaurants, bars and hotels. The shift by the card thieves away from targeting major retailers like Target and Home Depot to attacking countless, smaller users of POS systems is giving financial institutions a run for their money as they struggle to figure out which merchants are responsible for card fraud.
One basic tool that banks use to learn the source of card data theft involves determining a “common point-of-purchase” (CPP) among a given set of customer cards that experience fraud. When a new batch of cards goes on sale at an online crime shop, banks will often purchase a very small number of their stolen cards to determine if the victim customers all shopped at the same merchant across a specific time period.
This same CPP analysis was critical to banks helping this reporter identify some of the biggest retail breaches on record in recent years, and it is a method heavily relied upon by law enforcement agencies to identify breach victims.
But the CPP approach usually falls flat if all of the cards purchased from the fraud shop fail to reveal a common merchant. More seasoned fraud shops have sought to achieve this confusion and confound investigators by “making sausage” — i.e., methodically mixing cards stolen from multiple victims into any single new batch of stolen cards that they offer for sale.
Increasingly, however, fraudsters selling stolen cards don’t need to make sausage: The victims that are leaking card data are already subsets of restaurant franchises or retail establishments whose only commonality is the branded point-of-sale device which they rely upon to process customer card transactions.