Risks of Offline Verify PIN on Contactless Cards

Abstract

Contactless card payments are being introduced around the world allowing customers to use a card to pay for small purchases by simply placing the card onto the Point of Sale terminal. Contactless transactions do not require verification of the cardholder's PIN. However our research has found the redundant verify PIN functionality is present on the most commonly issued contactless credit and debit cards currently in circulation in the UK. This paper presents a plausible attack scenario which exploits contactless verify PIN to give unlimited attempts to guess the cardholder's PIN without their knowledge. It also gives experimental data to demonstrate the practical viability of the attack as well as references to support our argument that contactless verify PIN is redundant functionality which compromises the security of payment cards and the cardholder. AbstractContactless card payments are being introduced around the world allowing customers to use a card to pay for small purchases by simply placing the card onto the Point of Sale terminal. Contactless transactions do not require verification of the cardholder's PIN. However our research has found the redundant verify PIN functionality is present on the most commonly issued contactless credit and debit cards currently in circulation in the UK. This paper presents a plausible attack scenario which exploits contactless verify PIN to give unlimited attempts to guess the cardholder's PIN without their knowledge. It also gives experimental data to demonstrate the practical viability of the attack as well as references to support our argument that contactless verify PIN is redundant functionality which compromises the security of payment cards and the cardholder.

Relay Cost Bounding for Contactless EMV Payments

“…Furthermore, successful relay attacks on payWave have been reported in, for example, [11]. Their average time for a relayed transaction is 1.6s, which is an overhead of about 1.1s compared to a regular transaction.…”

“…Therefore the attacker will have more opportunities to perform the attack and it will be less clear for the user that anything is going on. That such attacks are possible using cheap hardware, namely mobile phones, has been demonstrated in, for example, [17,11,12,20].…”

A Methodology for Protocol Verification Applied to EMV® 1

“…This has proved to be effective in both documenting decisions precisely [20,21,25], and detecting significant protocol flaws early in the development process [19,18], way before deployment or actual implementations. Specifically, it is a variation of a successful industry approach by Praxis (now Altran UK, see www.adacore.com/sparkpro/tokeneer), where formal specifications are used to clarify requirements and then later used to inform its design and implementations.…”

“…In principle, payment protocols are designed to be secure, with adequate and effective cryptographic methods employed to ensure confidentiality, integrity, authentication, identification, etc. In practice, relevant attacks [9,17,19,18] still occur in the industry, with financial fraud related to payment systems rising in the last few years: for example, in the UK, there has been a 80 percent increase in value of losses between 2011 and 2016, when the fraud losses were £618 million [24].…”

NFC Payment Spy: A Privacy Attack on Contactless Payments

“…Contactless cards are always on and a malicious reader in the proximity of such a device is able to trigger a response from the card, without the user's awareness. A number of security and privacy violations have been reported in the literature exploiting such unauthorised readings [17]. More security attacks include different types of relay attacks such as Man-in-The-Middle and Mafia attacks [18,21,30,35].…”