Evan Schuman's StorefrontBacktalk

Macy’s (NYSE:M) has a courtesy policy in which if any Macy’s card shoppers come into a Macy’s and do not have their cards with them, they can still charge items to the card by inputting their Social Security number and showing the associate a government ID. It was precisely that policy that created a hole for an Indiana man to crawl through, charging thousands of dollars worth of merchandise to various Macy’s customers.

The precise methodology of the accused thief, Mark A. Douglas, is not clear, but he apparently created a list of Macy’s account holders and then used various techniques to learn their Social Security numbers. Making the false identifications—with the real shopper’s name and a picture of Douglas—seems to have been the easy part. Although sophisticated cyberthief techniques could have been used to create that list of Macy’s cardholders, it might also have been done as easily as standing near a Macy’s cashier and listening.

According to a Tippecanoe County, Indiana, affidavit of probable cause for arrest, the Indianapolis-based Douglas went into a Macy’s at the Tippecanoe Mall and used this technique to steal three Dyson vacuum cleaners, which cost $1,540.77. On that same day, Macy’s security footage saw Douglas—wearing the same clothes plus an identical tattoo on the right side of his neck—at another Macy’s, this time in Terre Haute, Ind. The affidavit said that Douglas has used this technique in various Macy’s repeatedly.

It’s unclear the nature of the bogus identification document shown at Macy’s in this incident, but Macy’s spokesperson Beth Charlton said the chain’s policy requires that only government IDs such as driver’s licenses be accepted. Charlton explained how the process is supposed to work: “If a customer comes into the store, selects merchandise, and doesn’t have their (Macy’s) card with them, the sales associate will ask them for a government or state photo ID. The customer is then asked to input their social security number into the signature pad. There is no verbal discussion about the ID information or the social security number. The sales associate does not see the social security number, only our credit office. If everything checks out, the customer will be allowed to charge the purchase.”

Macy’s policy is a good one for privacy. As it happens, it also could have made matters a little more safe for shoppers who are near eavesdropping thieves. Of course, this process could have also facilitated shoulder surfing, where the thief stands behind the customer and notes the digits being entered. Once done, the thief merely uses that information at any Macy’s in the country. (The thief could, in theory, also use it at that same Macy’s, but that makes it a slightly greater chance that someone might remember what the real customer looks like.)

Thieves could also simply access wallets in placed like gyms and find any that had Macy’s cards and then look for clues that would deliver Social Security numbers.

In this particular case, though, it sounds more like the suspect had database access to a list of Macy’s cardholders, given that one of the identified victims is from California and has apparently never been in an Indiana Macy’s, according to Det. William Dempster of the Lafeyette Police Department, which is handling the case.

One option for Macy’s is to take a page from Paypal and Square and have the customer’s picture flash on the POS screen, as a theoretically independent verification of the shopper.

A key problem with Social Security numbers is that far too many businesses—Macy’s among them—ask for the number as identification. That means that a shopper’s SS number is likely listed in countless databases that have nothing to do with the U.S. Social Security Adminstration. Hacking into any one of them—or simply have someone with access give it to criminal temptation—shows the foolhardiness of using that well-known (and very hard to change) number as identification. Some recent breaches have boasted that cyberthieves got no payment card data, only passwords and Social Security numbers. After all, what good would an SS number do a thief?