Fun with RFID tags
According to the article, things go even further than that:
And there's an even worse scenario: "It is only a matter of time
before someone puts a root exploit on one of these tags and hacks
into your supply chain," Grunwald said.
That scenario seems unlikely; the capacity of an RFID tag, and the uses to which the tags are put, do not afford many opportunities for the injection of shell code into point-of-sale systems. But, then, somebody might just pull it off.
The real security risk is the number of systems which will be programmed to
believe what their RFID readers are telling them. It is surprising that a
device meant to be used as an identification token is rewritable in this
way. It should not take too long before troublemakers with RFID writers
convince the retail establishment that this was a bad decision.