Researchers at UK-based Corsaire say the magnetic-stripe technology used for gift cards and customer loyalty cards -- as well as their easy accessibility -- make them attractive targets for the bad guys. Gift cards can easily be "sniffed" off the shelf in the checkout line with a scanner and then cloned; the card number on the back of the card stolen; and the retailers' Web-based gift card applications hacked.
"Gift cards are a type of currency and thus, they're likely to be targeted by fraudsters in the future, says Adrian Pastor, principal security consultant with Corsaire, which first revealed some of its gift card hack research at EUSecWest in May, "It looks like standardized security guidelines are needed for the gift card industry. We're hoping that our paper will serve as a good first step in accomplishing this."
Even unactivated gift cards are at risk: Corsaire says all a fraudster has to do is take one from a display in a retail store, scan it with the proper scanning device to clone it, and then use the card once an unsuspecting customer buys it and it's activated. "Although gift cards need to be at a visible location in stores to attract customers, they should not be at a location easily available for anyone to reach. Doing so would help stop attackers from cloning them and putting them back on the stand," Pastor says. "By doing this, all the attacker needs to do is wait for a customer to activate the gift card and load it with credit. Because the magstripe track data on these gift cards is the same before and after being activated, the attacker could now purchase goods for 'free.'"
Some gift cards display their card number on the back, which can provide a fraudster with enough information to clone a card, or even to redeem the gift card at the retailer, for instance. This way, they don't even have to swipe the magnetic stripe. And sometimes the gift card numbers are printed on sales receipts, the researchers noted. "Some gift card balance lookup sites only require users to enter their gift card number, whereas others also require PIN in addition to the card number," Pastor notes.
And like any Web application, a gift-card application has its vulnerabilities -- including the pervasive SQL injection flaw. "We also introduced some attacks which although we haven't tested, could work against certain implementations. For instance, manipulating a card's balanced in the back-end database by crafting magstripe data with malicious SQL statements," Pastor says.
An attacker could modify the gift card balance this way, for example. But this would require knowledge of the retailer's internal systems, so it would be difficult to execute.
A more realistic hack would be the gift-card programs administrative console, according to the researchers. That way, the attacker could set the balance of the card, for example.
Corsaire's Pastor says he was surprised how it's possible to attack at least two UK retail chains by brute-forcing gift-card numbers against the balance look-up site. "[You then] record card numbers that have been activated and their corresponding balance. Because in the two particular card implementations the track data can be fully derived from the card number, you can essentially clone an active card without ever having physical access to it," he says.
Pastor says gift cards should be secured like any other type of currency and electronic payment transaction.
Corsaire's research paper is available for download here.
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