Smart cards are most commonly used with readers for granting access to a facility or system. They can be used by themselves or with a PIN number in a two-factor authentication system. Smart cards requiring an additional PIN number use a technology called "Chip and PIN," which is popular in the UK and Europe.
The chips on smart cards are microprocessors, and can be either programmable or static. Either way, unlike the processor in a larger device, like a full-size laptop or workstation, they can only hold so much data. This can limit the size of the encryption keys they carry, which reduces the strength of the encryption protecting the card's data.
A number of researchers have found ways to hack smart cards by tampering with the microchip using light from camera flashbulbs and radio signals. But the most recent possible hack was demonstrated in February by two researchers in the UK. Saar Drimer and Steven Murdoch of Cambridge University found a way to steal data from a smart card by manipulating the terminal that reads the card. The researchers showed that the Chip and PIN technology, which is a government mandate in the UK, isn't as strong as its proponents claim.
Drimer and Murdoch found a way to bypass the encryption on the card by setting up a fake terminal that wasn't connected to a bank, but rather to a thief's laptop. The laptop is used to steal the card information as the unsuspecting user puts in his or her card and enters a PIN. The thief's laptop relays the information to an accomplice's laptop, which is connected to a fake card used for maliciously accessing the victim's bank account.
The researchers deliberately kept details from the media of how they manipulated the fake card to copy the data, claiming that they didn't want the information to fall into the wrong hands. But, in the same breath, the researchers suggested additional cryptographic handshakes could be added to the smart card transaction process to thwart this attack method.
Despite these types of attacks, smart cards shouldn't be discounted altogether as an authentication method to protect access to systems. They still offer a greater level of protection than user IDs and passwords, which can be easily stolen or guessed, and can be combined with other controls in a robust two-factor authentication system.
This was first published in March 2008