Don't believe what you read in the papers

News coverage, Politics

Yesterday the heads of “MI5”, “MI6” and GCHQ appeared before the Intelligence Security Committee of Parliament. The uncorrected transcript of their evidence is now online (or you can watch the video).

One of the questions fielded by Andrew Parker (“MI5”) was how many terrorist plots there had been over the past ten years. According to the uncorrected transcript (and this accords with listening to the video — question starts at 34:40) he said:

I think the number since… if I go back to 2005, rather than ten years… 7/7 is that there have been 34 plots towards terrorism that have been disrupted in this country, at all sizes and stages. I have referred publicly and previously, and my predecessors have, to the fact that one or two of those were major plots aimed at mass casualty that have been attempted each year. Of that 34, most of them, the vast majority, have been disrupted by active detection and intervention by the Agencies and the police. One or two of them, a small number, have failed because they just failed. The plans did not come together. But the vast majority by intervention.

I understand that to mean 34 plots over 8 years most but not all of which were disrupted, rather than just discovered. Of these, one or two per year were aimed at causing mass casualties (that’s 8 to 16 of them). I find it really quite surprising that such a rough guess of 8 to 16 major plots was not remarked upon by the Committee — but then they were being pretty soft generally in what they asked about.

The journalists who covered the story heard this all slightly differently, both as to how many plots were foiled by the agencies and how many were aimed at causing mass casualties!
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A new side channel attack

Academic papers, Banking security, Hardware & signals, Operating systems, Privacy technology, Security engineering, Usability

Today we’re presenting a new side-channel attack in PIN Skimmer: Inferring PINs Through The Camera and Microphone at SPSM 2013. We found that software on your smartphone can work out what PIN you’re entering by watching your face through the camera and listening for the clicks as you type. Previous researchers had shown how to work out PINs using the gyro and accelerometer; we found that the camera works about as well. We watch how your face appears to move as you jiggle your phone by typing.

There are implications for the design of electronic wallets using mechanisms such as Trustzone which enable some apps to run in a more secure sandbox. Such systems try to prevent sensitive data such as bank credentials being stolen by malware. Our work shows it’s not enough for your electronic wallet software to grab hold of the screen, the accelerometers and the gyro; you’d better lock down the video camera, and the still camera too while you’re at it. (Our attack can use the still camera in burst mode.)

We suggest ways in which mobile phone operating systems might mitigate the risks. Meanwhile, if you’re developing payment apps, you’d better be aware that these risks exist.

Offender tagging 2.0

Academic papers, Legal issues, News coverage, Security engineering

Three of our clients have been acquitted of tampering with curfew tags after the Ministry of Justice and G4S were unwilling to have an independent forensic team examine their evidence. This brings to five the number of tag-tampering prosecutions that have been withdrawn or collapsed when the defence says “Right, prove it then.” I reported the first case here.

The three latest matters were high-profile terrorism cases, involving three of the nine men tagged under the new Terrorism Prevention and Investigation Measure (TPIM) – a kind of national-security ASBO handed out by MI5, and which had already been criticised by David Anderson QC, the government’s independent reviewer of terrorism legislation, for low standards of proof. Unlike a normal ASBO which a court gives “on the balance of probabilities”, you can get a TPIM if the Home Secretary declares she has a “reasonable suspicion”.

The Ministry of Justice should perhaps, when they let the tagging contracts, have read our 1994 paper on the John Munden case, or the post here about the similar case of Jane Badger. If you’re designing a system one of whose functions is to provide evidence, you’d better design it to withstand hostile review. “Trust us” doesn’t cut it in criminal trials, and neither does “I’m afraid that’s commercially confidential.”

How to deal with emergencies better

Academic papers, Legal issues, News coverage, Politics, Security psychology

Britain has just been hit by a storm; two people have been killed by falling trees, and one swept out to sea. The rail network is in chaos and over 100,000 homes lost electric power. What can security engineering teach about such events?

Risk communication could be very much better. The storm had been forecast for several days but the instructions and advice from authority have almost all been framed in vague and general terms. Our research on browser warnings shows that people mostly ignore vague warnings (“Warning – visiting this web site may harm your computer!”) but pay much more attention to concrete ones (such as “The site you are about to visit has been confirmed to contain software that poses a significant risk to you, with no tangible benefit. It would try to infect your computer with malware designed to steal your bank account and credit card details in order to defraud you”). In fact, making warnings more concrete is the only thing that works here – nudge favourites such as appealing to social norms, or authority, or even putting a cartoon face on the page to activate social cognition, don’t seem to have a significant effect in this context.

So how should the Met Office and the emergency services deal with the next storm?

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We're hiring again

Security economics, Security engineering, Security psychology, Spam, Web security

We have a vacancy for a postdoc to work on the economics of cybercrime for two years from January. It might suit someone with a PhD in economics or criminology and an interest in online crime; or a PhD in computer science with an interest in security and economics.

Security economics has grown rapidly in the last decade; security in global systems is usually an equilibrium that emerges from the selfish actions of many independent actors, and security failures often follow from perverse incentives. To understand better what works and what doesn’t, we need both theoretical models and empirical data. We have access to various large-scale sources of data relating to cybercrime – email spam, malware samples, DNS traffic, phishing URL feeds – and some or all of this data could be used in this research. We’re very open-minded about what work might be done on this project; possible topics include victim analysis, malware analysis, spam data mining, data visualisation, measuring attacks, how security scales (or fails to), and how cybercrime data could be shared better.

This is an international project involving colleagues at CMU, SMU and the NCFTA.

A Study of Whois Privacy and Proxy Service Abuse

Academic papers, Security economics, Web security

ICANN have now published a draft for public comment of “A Study of Whois Privacy and Proxy Service Abuse“. I am the primary author of this report — the work being done whilst I was collaborating with the National Physical Laboratory (NPL) under EPSRC Grant EP/H018298/1.

This particular study was originally proposed by ICANN in 2010, one of several that were to examine the impact of domain registrants using privacy services (where the name of a domain registrant is published, but contact details are kept private) and proxy services (where even the domain licensee’s name is not made available on the public database).

ICANN wanted to know if a significant percentage of the domain names used to conduct illegal or harmful Internet activities are registered via privacy or proxy services to obscure the perpetrator’s identity? No surprises in our results: they are!

However, it’s more interesting to ask whether this percentage is somewhat higher than the usage of privacy or proxy services for entirely lawful and harmless Internet activities? This turned out NOT to be the case — for example banks use privacy and proxy services almost as often as the registrants of domains used in the hosting of child sexual abuse images; and the registrants of domains used to host (legal) adult pornography use privacy and proxy services more often than most (but not all) of the different types of malicious activity that we studied.

It’s also relevant to consider what other methods might be chosen by those involved in criminal activity to obscure their identities, because in the event of changes to privacy and proxy services, it is likely that they will turn to these alternatives.

Accordingly, we determined experimentally whether a significant percentage of the domain names we examined have been registered with incorrect Whois contact information – and specifically whether or not we could reach the domain registrant using a phone number from the Whois information. We asked them a single question in their native language “did you register this domain”?

We got somewhat variable results from our phone survey — but the pattern becomes clear if we consider whether there is any a priori hope at all of ringing up the domain registrant?

If we sum up the likelihoods:

  • uses privacy or proxy service
  • no (apparently valid) phone number in whois
  • number is apparently valid, but fails to connect
  • number reaches someone other than the registrant

then we find that for legal and harmless activities the probability of a phone call not being possible ranges between 24% (legal pharmacies on the Legitscript list) and 62% (owners of lawful websites that someone has broken into and installed phishing pages). For malicious activities the probability of failure is 88% or more, with typosquatting (which is a civil matter, rather than a criminal one) sitting at 68% (some of the typosquatters want to hide, some do not).

There’s lots of detail and supporting statistics in the report… and an executive summary for the time-challenged. It will provide real data, rather than just speculative anecdotes, to inform the debate around reforming Whois — and the difficulties of doing so.

Google funding of open-source security projects

Open-source security, Operating systems, Security engineering

I was pleased to contribute to a recent blog article by Ben Laurie, a frequent collaborator with the Cambridge security group, on the Google Open Source Programs Office blog. We describe open-source security work OSPO has sponsored over the last couple of years, including our joint work on Capsicum, and its followup projects funded jointly by Google and the FreeBSD Foundation. He also talks about Google support for Certificate Transparency, OpenSSL, Tor, and Libpurple — projects focussed not just on communications security, but also communications privacy on the Internet.

Capsicum

Over the last decade or so, it has become increasingly (and painfully) apparent that ACLs and MAC, which were originally designed to protect expensive mainframes from their users, and the users from each other, are failing to secure modern cheap machines with single users who need protecting from the software they run.

Instead, we need fine-grained access control and strong sandboxing.
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Offender tagging

Hardware & signals, Legal issues, News coverage, Politics, Usability

August was a slow month, but we got a legal case where our client was accused of tampering with a curfew tag, and I was asked for an expert report on the evidence presented by Serco, the curfew tagging contractor. Many offenders in the UK are released early (or escape prison altogether) on condition that they stay at home from 8pm to 8am and wear an ankle bracelet so their compliance can be monitored. These curfew tags have been used for fourteen years now but are controversial for various reasons; but with the prisons full and 17,500 people on tag at any one time, the objective of policy is to improve the system rather than abolish it.

In this spirit I offer a redacted version of my expert report which may give some insight into the frailty of the system. The logs relating to my defendant’s case showed large numbers of false alarms; some of these had good explanations (such as power cuts) but many didn’t. The overall impression is of an unreliable technology surrounded by chaotic procedures. Of policy concern too is that the tagging contractor not only supplies the tags and the back-end systems, but the call centre and the interface to the court system. What’s more, if you break your curfew, it isn’t the Crown Prosecution Service that takes you before the magistrates, but the contractor – relying on expert evidence from one of its subcontractors. Such closed systems are notoriously vulnerable to groupthink. Anyway, we asked the court for access not just to the tag in the case, but a complete set of tagging equipment for testing, plus system specifications, false alarm statistics and audit reports. The contractor promptly replied that “although we continue to feel that the defendant is in breach of the order, our attention has been drawn to a number of factors that would allow me to properly discontinue proceedings in the public interest.”

The report is published with the consent of my client and her solicitor. Long-time readers of this blog may recall similarities with the case of Jane Badger. If you’re designing systems on whose output someone may have to rely in court, you’d better think hard about how they’ll stand up to hostile review.

NSA Award for Best Scientific Cybersecurity Paper

Academic papers, Authentication, Awards

Yesterday I received the NSA award for the Best Scientific Cybersecurity Paper of 2012 for my IEEE Oakland paper “The science of guessing.” I’m honored to have been recognised by the distinguished academic panel assembled by the NSA. I’d like to again thank Henry Watts, Elizabeth Zwicky, and everybody else at Yahoo! who helped me with this research while I interned there, as well as Richard Clayton and Ross Anderson for their support and supervision throughout.

On a personal note, I’d be remiss not to mention my conflicted feelings about winning the award given what we know about the NSA’s widespread collection of private communications and what remains unknown about oversight over the agency’s operations. Like many in the community of cryptographers and security engineers, I’m sad that we haven’t better informed the public about the inherent dangers and questionable utility of mass surveillance. And like many American citizens I’m ashamed we’ve let our politicians sneak the country down this path.

In accepting the award I don’t condone the NSA’s surveillance. Simply put, I don’t think a free society is compatible with an organisation like the NSA in its current form. Yet I’m glad I got the rare opportunity to visit with the NSA and I’m grateful for my hosts’ genuine hospitality. A large group of engineers turned up to hear my presentation, asked sharp questions, understood and cared about the privacy implications of studying password data. It affirmed my feeling that America’s core problems are in Washington and not in Fort Meade. Our focus must remain on winning the public debate around surveillance and developing privacy-enhancing technology. But I hope that this award program, established to increase engagement with academic researchers, can be a small but positive step.