On Square Skimmer Security Risks

There’s an “open letter” going around about the alleged security hole created by SquareUp, a startup that gives out free credit card readers for smart phones. To quote the meat of it:

In less than an hour, any reasonably skilled programmer can write an application that will “skim” – or steal – a consumer’s financial and personal information right off the card utilizing an easily obtained Square card reader. How do we know? We did it. Tested on sample Square card readers with our own personal credit cards, we wrote an application in less than an hour that did exactly this.

Allow me to debunk the hell out of this:

  • To skim a card you need physical possession of the card. The numbers are printed on the front. No reader needed.
  • Skimming is normally done by attaching a device in front of a legitimate reader (such as an ATM) so it passively collects data. Not via cell phone. Stealing a credit card, walking to a back ally and skimming doesn’t make any sense.
  • Credit cards numbers are worth almost nothing on the black market. They are sold in bulk. This process is to slow to be viable for even the most brain-dead of criminals to want to bother with.
  • There are easier methods than the above including phishing attacks, becoming a waiter (the best job for credit card thieves), or just hacking one of the many insecure ecommerce sites on the net. An ATM skimmer attached to an ATM is much more profitable and harder to get caught since you can leave and come back later.
  • Square’s dongle doesn’t encrypt data because it goes directly to the phone. You’d need to extensively modify the device to intercept anything. The connection from your phone to Square seems to be encrypted.
  • Oh yea… They have their logo on top, but never link to their homepage or explain who they are. VeriFone is a vendor of credit card scanners. A direct competitor of Square. They also sell wireless scanners that would compete directly with Square. They cost a lot.

How’d I do?

Bonus:

VeriFone sells “contactless” point of sale systems. I’ve mentioned several times over the past few years how poorly thought out these seem to be. WREG recently did a great story on how easy it is to scan/clone one of these cards to a hotel key (full disclosure: WREG is an affiliate of my employer).

Conclusion:

If someone steals your credit card swiping it on their own scanner, reads the numbers off, or just running to the nearest store and buying things, it doesn’t make a difference. Square isn’t the security hole here.

I’ve got a square reader on hand and can say it’s cheaply made (obviously), but no reason at all to think it’s any less secure than any other terminal. The owner/operator of the terminal is the chief point of failure.