Monthly Archives: May 2014

Light Blue Touchpaper now on HTTPS

Authentication, Cryptology, Meta, Web security

Light Blue Touchpaper now supports TLS, so as to protect passwords and authentication cookies from eavesdropping. TLS support is provided by the Pound load-balancer, because Varnish (our reverse-proxy cache) does not support TLS.

The configuration is intended to be a reasonable trade-off between security and usability, and gets an A– on the Qualys SSL report. The cipher suite list is based on the very helpful Qualys Security Labs recommendations and Apache header re-writing sets the HttpOnly and Secure cookie flags to resist cookie hijacking.

As always, we might have missed something, so if you notice problems such as incompatibilities with certain browsers, then please let us know on <lbt-admin@cl.cam.ac.uk>. or in the comments.

Post-Snowden: the economics of surveillance

Academic papers, News coverage, Politics, Privacy technology, Security economics

After 9/11, we worked on the economics of security, in an attempt to bring back some rationality. Next followed the economics of privacy, which Alessandro Acquisti and others developed to explain why people interact with social media the way they do. A year after the Snowden revelations, it’s time to talk about the economics of surveillance.

In a new paper I discuss how information economics applies to the NSA and its allies, just as it applies to Google and Microsoft. The Snowden papers reveal that the modern world of signals intelligence exhibits strong network effects which cause surveillance platforms to behave much like operating systems or social networks. So while India used to be happy to buy warplanes from Russia (and they still do), they now share intelligence with the NSA as it has the bigger network. Networks also tend to merge, so we see the convergence of intelligence with law enforcement everywhere, from PRISM to the UK Communications Data Bill.

There is an interesting cultural split in that while the IT industry understands network effects extremely well, the international relations community pays almost no attention to it. So it’s not just a matter of the left coast thinking Snowden a whistleblower and the right coast thinking him a traitor; there is a real gap in the underlying conceptual analysis.

That is a shame. The global surveillance network that’s currently being built by the NSA, GCHQ and its collaborator agencies in dozens of countries may become a new international institution, like the World Bank or the United Nations, but more influential and rather harder to govern. And just as Britain’s imperial network of telegraph and telephone cables survived the demise of empire, so the global surveillance network may survive America’s pre-eminence. Mr Obama might care to stop and wonder whether the amount of privacy he extends to a farmer in the Punjab today might be correlated with with amount of privacy the ruler of China will extend to his grandchildren in fifty years’ time. What goes around, comes around.

The pre-play vulnerability in Chip and PIN

Academic papers, Banking security, Cryptology, Hardware & signals

Today we have published a new paper: “Chip and Skim: cloning EMV cards with the pre-play attack”, presented at the 2014 IEEE Symposium on Security and Privacy. The paper analyses the EMV protocol, the leading smart card payment system with 1.62 billion cards in circulation, and known as “Chip and PIN” in English-speaking countries. As a result of the Target data breach, banks in the US (which have lagged behind in Chip and PIN deployment compared to the rest of the world) have accelerated their efforts to roll out Chip and PIN capable cards to their customers.

However, our paper shows that Chip and PIN, as currently implemented, still has serious vulnerabilities, which might leave customers at risk of fraud. Previously we have shown how cards can be used without knowing the correct PIN, and that card details can be intercepted as a result of flawed tamper-protection. Our new paper shows that it is possible to create clone chip cards which normal bank procedures will not be able to distinguish from the real card.

When a Chip and PIN transaction is performed, the terminal requests that the card produces an authentication code for the transaction. Part of this transaction is a number that is supposed to be random, so as to stop an authentication code being generated in advance. However, there are two ways in which the protection can by bypassed: the first requires that the Chip and PIN terminal has a poorly designed random generation (which we have observed in the wild); the second requires that the Chip and PIN terminal or its communications back to the bank can be tampered with (which again, we have observed in the wild).

To carry out the attack, the criminal arranges that the targeted terminal will generate a particular “random” number in the future (either by predicting which number will be generated by a poorly designed random number generator, by tampering with the random number generator, or by tampering with the random number sent to the bank). Then the criminal gains temporary access to the card (for example by tampering with a Chip and PIN terminal) and requests authentication codes corresponding to the “random” number(s) that will later occur. Finally, the attacker loads the authentication codes on to the clone card, and uses this card in the targeted terminal. Because the authentication codes that the clone card provides match those which the real card would have provided, the bank cannot distinguish between the clone card and the real one.

Because the transactions look legitimate, banks may refuse to refund victims of fraud. So in the paper we discuss how bank procedures could be improved to detect whether this attack has occurred. We also describe how the Chip and PIN system could be improved. As a result of our research, work has started on mitigating one of the vulnerabilities we identified; the certification requirements for random number generators in Chip and PIN terminals have been improved, though old terminals may still be vulnerable. Attacks making use of tampered random number generators or communications are more challenging to prevent and have yet to be addressed.

Update (2014-05-20): There is press coverage of this paper in The Register, SC Magazine UK and Schneier on Security.
Update (2014-05-21): Also now covered in The Hacker News.

Small earthquake, not many dead (yet)

Banking security, Internet censorship, Legal issues, News coverage, Politics, Privacy technology, Security economics, Social networks

The European Court of Justice decision in the Google case will have implications way beyond search engines. Regular readers of this blog will recall stories of banks hounding innocent people for money following payment disputes, and a favourite trick is to blacklist people with credit reference agencies, even while disputes are still in progress (or even after the bank has actually lost a court case). In the past, the Information Commissioner refused to do anything about this abuse, claiming that it’s the bank which is the data controller, not the credit agency. The court now confirms that this view was quite wrong. I have therefore written to the Information Commissioner inviting him to acknowledge this and to withdraw the guidance issued to the credit reference agencies by his predecessor.

I wonder what other information intermediaries will now have to revise their business models?