The EMV of Payment Terminals – SHA-1

9 Mar

Never one to shy away from even the MOST ARCANE areas of payments… There is a firestorm in payments encryption right now.. SHA-1 is a hashing function (securing data for a counterparty without the use of public/private keys) that has long since been sunsetted by Microsoft, Google and others as “too weak” and “easily cracked”. Unfortunately hundreds of thousands of payment terminals rely on this technology and the these terminals rely on root servers to validate the certificates. Mozilla and others had planned to sunset the support of SHA-1 within their root CA servers but then had BANKs like Worldpay beg them for another extension.. as thousands of merchant POS terminals would stop working instantly.

The sunsetting of SHA-1 is over 5 years old.. and no one took action? My retailer friends have been at the receiving end of poor security press 99% of the time. This is the first time that banks (acquirers) have been caught with their “back door open” and the press is abuzz.

5 thoughts on “The EMV of Payment Terminals – SHA-1”

  1. From a logical, risk based approach while reviewing this matter, there are several issues to consider:

    1. The Holy Grail of payments attacks is monetization of stolen data. The work factor, coupled with the potential for data recovery from a SHA-1 hash collision is minimal. There are many other methods employed by the criminals that yield a much higher ROCE** (return on criminal effort)

    2. The Certificate Authority / Browser Forum hxxp://cabforum.org established in 2012 is primarily concerned with Web Browser use cases for the PKI trust model. Historically, they’ve had very little concern for non browser based use cases. While there may be more risk associated with hash collisions affecting browser based use cases (successful Man in the Middle attacks, etc) October 2nd 2015 the CA/B Forum was considering a ballot to continue issuing SHA-1 certificates through 2016. See Ballot 152 which was proposed by Symantec and endorsed by EnTrust, Microsoft and Trend Micro.

    3. A Freestart collision for SHA-1 may result in signature forgeries, but don’t break the entire Internet according to the researchers that discovered the attack.

    ** Feel free to use ROCE but kindly credit ThePaymentsGuy 😉

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