Category Archives: Academic papers

AlphaBay and Hansa Market takedowns

Yesterday the FBI announced the takedown of the AlphaBay marketplace, a hidden service facilitating the sale of drugs, as well as other illicit products and services. The takedown had actually occurred weeks earlier, and had been staged to appear like an exit scam, where the operators take off with the money.

What was particularly interesting about the FBI’s takedown was that it was coordinated with the activities of the Dutch police, who had previously taken over the Hansa Market, another leading blackmarket. As the investigators were then controlling this marketplace they were able to monitor the activities of traders who had been using AlphaBay and then moved to Hansa Market.

I’ve been interested in online blackmarkets for some time, particularly those that relate to the stolen data economy. In fact, last year a paper written by Professor Thomas Holt and I was published. This paper outlines a number of intervention approaches, including disrupting the actual marketplaces where trade takes place.

Among our numerous suggestions are three that have been used, in combination, by this international police effort. We suggest that law enforcement promote distrust, which they did by making AlphaBay appear to have been an exit scam. We also suggest that law enforcement take over and take down marketplaces. Neither of these police approaches are new, and we point to previous examples where this has happened. In our conclusion, we stated:

Multiple interventions coordinated across different guardians, nationally and internationally, incorporating different bodies (investigative, regulatory, strategic, non-government organisations and the private sector) that have ownership of the crime prevention problem may reduce duplication of effort, as well as provide a more systematic approach with the greatest disruption effect.

The Hansa Market and AlphaBay approach demonstrates how this can be achieved. By co-ordinating the approaches, and working together, the disruptive effects of their work is likely to be much greater than if they had acted alone. It’s likely we’ll see arrests of traders and further disruption to the online drug trade.

Work by Soska and Christin found that after the Silk Road takedown, more online blackmarkets emerged and evolved. I think this evolution will continue, but perhaps marketplace administrators will have to work harder in order to earn the trust of their users.

Testing the usability of offline mobile payments

Last September we spent some time in Nairobi figuring out whether we could make offline phone payments usable. Phone payments have greatly improved the lives of millions of poor people in countries like Kenya and Bangladesh, who previously didn’t have bank accounts at all but who can now send and receive money using their phones. That’s great for the 80% who have mobile phone coverage, but what about the others?

Last year I described how we designed and built a prototype system to support offline payments, with the help of a grant from the Bill and Melinda Gates Foundation, and took it to Africa to test it. Offline payments require both the sender and the receiver to enter some extra digits to ensure that the payer and the payee agree on who’s paying whom how much. We worked as hard as we could to minimise the number of digits and to integrate them into the familar transaction flow. Would this be good enough?

Our paper setting out the results was accepted to the Symposium on Usable Privacy and Security (SOUPS), the leading security usability event. This has now started and the paper’s online; the lead author, Khaled Baqer, will be presenting it tomorrow. As we noted last year, the DigiTally pilot was a success. For the data and the detailed analysis, please see our paper:

DigiTally: Piloting Offline Payments for Phones, Khaled Baqer, Ross Anderson, Jeunese Adrienne Payne, Lorna Mutegi, Joseph Sevilla, 13th Symposium on Usable Privacy & Security (SOUPS 2017), pp 131–143

Camouflage or scary monsters: deceiving others about risk

I have just been at the Cambridge Risk and Uncertainty Conference which brings together people who educate the public about risks. They include public-health doctors trying to get people to eat better and exercise more, statisticians trying to keep governments honest about crime statistics, and climatologists trying to educate us about global warming – an eclectic and interesting bunch.

Most of the people in this community see their role as dispelling ignorance, or motivating the slothful. Yet in most of the cases we discussed, the public get risk wrong because powerful interests make a serious effort to scare them about some of life’s little hazards, or to reassure them about others. When this is put to the risk communication folks in a question – whether after a talk or in the corridor – they readily admit they’re up against a torrent of misleading marketing. But they don’t see what they’re doing as adversarial, and I strongly suspect that many risk interventions are less effective as a result.

In my talk (slides) I set this out as simply and starkly as I could. We spend too much on terrorism, because both the terrorists and the governments who’re supposed to protect us from them big up the threat; we spend too little on cybercrime, because everyone from the crooks through the police and the banks to the computer industry has their own reason to talk down the threat. I mentioned recent cases such as Wannacry as examples of how institutions communicate risk in self-serving, misleading ways. I discussed our own study of browser warnings, which suggests that people at least subconsciously know that most of the warnings they see are written to benefit others rather than them; they tune out all but the most specific.

What struck me with some force when preparing my talk, though, is that there’s just nobody in academia who takes a holistic view of adversarial risk communication. Many people look at some small part of the problem, from David Rios’ game-theoretic analysis of adversarial risk through John Mueller’s studies of terrorism risk and Alessandro Acquisti’s behavioural economics of privacy, through to criminologists who study pathways into crime and psychologists who study deception. Of all these, the literature on deception might be the most relevant, though we should also look at politics, propaganda, and studies of why people stubbornly persist in their beliefs – including the excellent work by Bénabou and Tirole on the value people place on belief. Perhaps the professionals whose job comes closest to adversarial risk communication are political spin doctors. So when should we talk about new facts, and when should we talk about who’s deceiving you and why?

Given the current concern over populism and the role of social media in the Brexit and Trump votes, it might be time for a more careful cross-disciplinary study of how we can change people’s minds about risk in the presence of smart and persistent adversaries. We know, for example, that a college education makes people much less susceptible to propaganda and marketing; but what is the science behind designing interventions that are quicker and cheaper in specific circumstances?

Second Annual Cybercrime Conference

The Cambridge Cybercrime Centre is organising another one day conference on cybercrime on Thursday, 13th July 2017.

In future years we intend to focus on research that has been carried out using datasets provided by the Cybercrime Centre, but just as last year (details here, liveblog here) we have a stellar group of invited speakers who are at the forefront of their fields:

They will present various aspects of cybercrime from the point of view of criminology, policy, security economics, law and policing.

This one day event, to be held in the Faculty of Law, University of Cambridge will follow immediately after (and will be in the same venue as) the “Tenth International Conference on Evidence Based Policing” organised by the Institute of Criminology which runs on the 11th and 12th July 2016.

Full details (and information about booking) is here.

When safety and security become one

What happens when your car starts getting monthly upgrades like your phone and your laptop? It’s starting to happen, and the changes will be profound. We’ll be able to improve car safety as we learn from accidents, and fixing a flaw won’t mean spending billions on a recall. But if you’re writing navigation code today that will go in the 2020 Landrover, how will you be able to ship safety and security patches in 2030? In 2040? In 2050? At present we struggle to keep software patched for three years; we have no idea how to do it for 30.

Our latest paper reports a project that Éireann Leverett, Richard Clayton and I undertook for the European Commission into what happens to safety in this brave new world. Europe is the world’s lead safety regulator for about a dozen industry sectors, of which we studied three: road transport, medical devices and the electricity industry.

Up till now, we’ve known how to make two kinds of fairly secure system. There’s the software in your phone or laptop which is complex and exposed to online attack, so has to be patched regularly as vulnerabilities are discovered. It’s typically abandoned after a few years as patching too many versions of software costs too much. The other kind is the software in safety-critical machinery which has tended to be stable, simple and thoroughly tested, and not exposed to the big bad Internet. As these two worlds collide, there will be some rather large waves.

Regulators who only thought in terms of safety will have to start thinking of security too. Safety engineers will have to learn adversarial thinking. Security engineers will have to think much more about ease of safe use. Educators will have to start teaching these subjects together. (I just expanded my introductory course on software engineering into one on software and security engineering.) And the policy debate will change too; people might vote for the FBI to have a golden master key to unlock your iPhone and read your private messages, but they might be less likely to vote them a master key to take over your car or your pacemaker.

Researchers and software developers will have to think seriously about how we can keep on patching the software in durable goods such as vehicles for thirty or forty years. It’s not acceptable to recycle cars after seven years, as greedy carmakers might hope; the embedded carbon cost of a car is about equal to its lifetime fuel burn, and reducing average mileage from 200,000 to 70,000 would treble the car industry’s CO2 emissions. So we’re going to have to learn how to make software sustainable. How do we do that?

Our paper is here; there’s a short video here and a longer video here.

Pico in the Wild: Replacing Passwords, One Site at a Time

The Pico team have just returned from Paris, where Kat Krol presented at both EuroS&P and the affiliated EuroUSEC workshop on usable security.

Pico is an ERC-funded project, led by Frank Stajano, to liberate humanity from passwords. It lets you log into devices and websites without having to remember any secrets. It relies on “something you have”: in the current prototype, that’s your smartphone, potentially coupled with other wearables, though high-security niche applications could use a dedicated token instead.

Our latest paper presents a new study performed in collaboration with the Gyazo.com website, where we invited users to test out the Pico authentication app for logging in to the site. A QR code was displayed on the Gyazo login page for the duration of the trial, allowing users to access their images simply by scanning the QR code and avoiding the need to enter a username or password.

Participants used Pico for two weeks, during which time we collected feedback using telemetry data, questionnaires and phone interviews. Our aim was to conduct a trial with high ecological validity, avoiding the usual lab-based studies which can run the risk of collecting intentions rather than actual behaviour.

Some of the key results from the paper are that participants liked the idea of Pico and generally found it to be secure and less cognitively demanding than passwords. However, some disliked the need to scan QR codes and suggested replacing them with another modality of interaction. There was also a general consensus that participants wanted to see Pico extended for use with more sites. The pain of password entry on any particular site isn’t so great, but when you scale it up to the plurality of sites we all routinely have to deal with, it becomes a much more serious burden.

The study attracted participants from all over the world, including Brazil, Greece, Japan, Latvia, Spain and the United States. However, it also highlighted some of the challenges of performing experimental studies ‘in the wild’. From an initial pool of seven million potential participants – the number of active users of the Gyazo photo sharing site – after reducing down to those users who entered passwords more regularly on the site and who were willing to participate in the study, we eventually recruited twelve participants to test out Pico. Not as many as we’d hoped for.

In the paper we discuss some of the reasons for this, including the fact that popular websites attempt to minimise the annoyance of password entry through the use of mechanisms such as long-lived cookies and dedicated apps.

While the purpose of the paper is to explore usable security and end-user reactions, it also allowed us to test out the Pico nginx reverse-proxy lens. Using this we could deploy Pico to the Gyazo website as in-page Javascript, demonstrating seamless deployment (zero changes to the backend Gyazo code) and removing the need for the user to install a browser plugin. The tech worked like a charm throughout the trial.

The paper is available from the Internet Society and the abstract for Kat’s short talk, covering future Pico evaluation studies, is available from the EuroS&P website.

1000 days of UDP amplification DDoS attacks

 

We presented “1000 days of UDP amplification DDoS attacks” at APWG’s eCrime 2017 conference last week in Scottsdale Arizona. The paper is here, and the slides from Daniel Thomas’s talk are here.

Distributed Denial of Service (DDoS) attacks employing reflected UDP amplification are regularly used to disrupt networks and systems. The amplification allows one rented server to generate significant volumes of data, while the reflection hides the identity of the attacker. Consequently this is an attractive, low risk, strategy for criminals bent on vandalism and extortion. Despite this, many of these criminals have been arrested.

These reflected UDP amplification attacks work by spoofing the source IP address on UDP packets sent from networks that negligently fail to implement BCP38/SAVE. Since UDP (unlike TCP) does not validate the source address, the much larger responses go to the attacker’s intended victim as they spoof the victim’s address on the packets they send out. There are many protocols that can be exploited in this way including DNS and NTP.

To measure the use of this strategy we analysed the results of running a network of honeypot UDP reflectors from July 2014 onwards. We explored the life cycle of attacks that use our honeypots, from the scanning phase used to detect our honeypot machines, through to their use in attacks. We see a median of 1450 malicious scanners per day across all UDP protocols, and have recorded details of 5.18 million subsequent attacks involving in excess of 3.31 trillion packets. We investigated the length of attacks and found that most are very short, but some last for days.

To estimate the total number of attacks that occurred, including those our honeypots did not observe, we used a capture-recapture statistical technique. From this we estimated that our honeypots can see between 85.1% and 96.6% of UDP reflection attacks over our measurement period.

We observe wide variation in the number of attacks per day over the course of the measurement period as attacks using different protocols went in and out of fashion.

This work is ongoing and data from our honeypot network is available to researchers through the Cambridge Cybercrime Centre.

Also, if you want to help stop these attacks being possible you could help CAIDA by
running their spoofer prober software that checks which ISPs are negligently failing to implement BCP38/SAVE.

Configuring Zeus

We presented “Configuring Zeus: A case study of online crime target selection and knowledge transmission” at APWG’s eCrime 2017 conference this past week in Scottsdale Arizona. The paper is here, and the slides from Richard Clayton’s talk are here.

Zeus (sometimes called Zbot) is a family of credential stealing malware which was widely deployed from 2007 to 2012 or so. It belongs to a class of malware dubbed ‘man-in-the-browser‘ (a play on a ‘man in the middle attack’) in that it runs on end-user machines where it can intercept web browser traffic to extract login credentials or to manipulate the page content displayed to the user.

It has been used to attack large numbers of sites, mainly banks — its extreme flexibility is achieved with ‘configuration files’ that indicate which websites are to be targeted, which user submitted fields are to be collected, what webpage rewriting (so called ‘webinjects’) is required and where the results are to be sent.

The complexity of these files seem to have restricted the number of websites actually targeted. In a paper presented at WEIS 2014 Tajalizadehkhoob et al. examined a large number of configuration files and described this lack of development and measured a substantial overlap in the content of different files. As a result, the authors suggested that offenders were not developing configuration files from scratch but were selling, sharing or stealing them.

We decided to test out this conjecture by seeking out messages about Zeus configuration files on underground forums (many of these are have been scraped, leaked or confiscated by law enforcement) — and this paper describes how we found evidence to support all three mechanisms: selling, sharing and stealing.

The paper also gives an account of the history of Zeus with illustrations from the messages that were uncovered along with clear evidence the release of tools to decrypt configuration files by security researchers was also closely followed on the forums, and assisted offenders when it came to stealing configuration files from others.