Zeus targets major retailers

Trusteer recently discovered a Zeus botnet that is targeting credit card accounts of major retailers including Macy’s and Nordstrom just as the holiday gift buying season is in full swing.

They captured and analyzed malware samples designed to steal credit card information, probably in order to conduct card-not-present (CNP) fraud. This attack is using a Zeus botnet – the latest and most sophisticated version of the Zeus malware platform.

CNP fraud refers to transactions when a credit card is not physically present, as in an internet, mail or phone purchase. It is difficult for a merchant to verify that the actual cardholder is indeed authorizing the purchase. Because of the greater risk, card issuers tend to charge merchants higher fees for CNP transactions.

To make matters worse, merchants are typically responsible for CNP fraud transactions. Therefore, CNP merchants must take extra precaution against fraud exposure and associated losses.

The attack uses social engineering to gather additional information beyond the credit card number that will make it easier for the criminal to bypass fraud detection measures used to investigate suspicious transactions.

In this case, the social engineering method used is very credible since the victim has navigated to the card issuer’s website – www.macys.com and www.nordstromcard.com – when Zeus injects a legitimate looking man-in-the-middle pop-up that requests personally identifiable information:

Merchants and card issuers invest a great deal in backend technologies for detecting fraudulent transactions. These systems represent an important security layer, however the increase in malware and phishing attacks that specifically target card information is making them less effective. An additional layer that can prevent card information from being stolen in the first place is now required.

As this latest Zeus configuration demonstrates, criminals are constantly evolving and refining their attack methods. While merchants and card issuers can’t adapt their security infrastructure as quickly as criminal groups can modify their attacks, they need to accept when current protection methods are not no longer sufficient and refresh their defense mechanisms accordingly.

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