Chip and Skim: cloning EMV cards with the pre-play attack
Worrying stuff from the LBT team. ATM RNGs are predictable, and can be spoofed by intermediate parties:
‘So far we have performed more than 1000 transactions at more than 20 ATMs and a number of POS terminals, and are collating a data set for statistical analysis. We have developed a passive transaction logger which can be integrated into the substrate of a real bank card, which records up to 100 unpredictable numbers in its EEPROM. Our analysis is ongoing but so far we have established non-uniformity of unpredictable numbers in half of the ATMs we have looked at. First, there is an easier attack than predicting the RNG. Since the unpredictable number is generated by the terminal but the relying party is the issuing bank, any intermediate party – from POS terminal software, to payment switches, or a middleman on the phone line – can intercept and superimpose their own choice of UN. Attacks such as those of Nohl and Roth, and MWR Labs show that POS terminals can be remotely hacked simply by inserting a sabotaged smartcard into the terminal.
(tags: atm banking security attack prngs spoofing banks chip-and-pin emv smartcards)