Speaking at the world’s largest hacking convention, Zac Franken is said to have demonstrated how an ordinary proximity card can be used alongside a programmable chip to gain access to restricted areas protected by any card reader employing the Wiegand protocol.
Made popular on proximity devices in the 1980s, the Wiegand protocol is the system of wires that verifies data when an access card is swiped in front of a card reader.
The Washington Post said:
“By embedding a simple program into a programmable chip and splicing it into the cabling on the back end of the unit, Franken showed how it was possible to use any proximity card to trick the device into replaying the code associated with the card of the person who most recently entered the protected area.”
It was also reported that by making a small change to the code, Franken could prevent all other cards from gaining access through the system again.
He is said to have told the audience at the DEFCON convention in Las Vegas that many card readers are open to this kind of attack because they are only protected by two screws and a plastic cover. If the cover is removed, the hacker can place a tiny PIC chip between two wires to ‘trick’ the system into allowing access.
The Washington Post said the Franken blamed the protocol itself on the worrying security weaknesses, and he recommended that companies using the technology invest in readers with tamper protection and/or security cameras.