Category Archives: Cybercrime

Grasping at straw

Britain’s National Crime Agency has spent the last five years trying to undermine encryption, saying it might stop them arresting hundreds of men every month for downloading indecent images of children. Now they complain that most of the men they do prosecute escape jail. Eight in ten men convicted of image offences escaped an immediate prison sentence, and the NCA’s Director General Graeme Biggar describes this as “striking”.

I agree, although the conclusions I draw are rather different. In Chatcontrol or Child Protection? I explained how the NCA and GCHQ divert police resources from tackling serious contact offences, such as child rape and child murder, to much less serious secondary offences around images of historical abuse and even synthetic images. The structural reasons are simple enough: they favour centralised policing over local efforts, and electronic surveillance over community work.

One winner is the NCA, which apparently now has 200 staff tracing people associated with alarms raised automatically by Big Tech’s content surveillance, while the losers include Britain’s 43 local police forces. If 80% of the people arrested as a result of Mr Biggar’s activities don’t even merit any jail time, then my conclusion is that the Treasury should cut his headcount by at least 160, and give each Chief Constable an extra 3-4 officers instead. Frontline cops agree that too much effort goes into image offences and not enough into the more serious contact crimes.

Mr Biggar argues that Facebook is wicked for turning on end-to-end encryption in Facebook Messenger, as won’t be able to catch as many bad men in future. But if encryption stops him wasting police time, well done Zuck! Mr Biggar also wants Parliament to increase the penalties. But even though Onan was struck dead by God for spilling his seed upon the ground, I hope we can have more rational priorities for criminal law enforcement in the 21st century.

How hate sites evade the censor

On Tuesday we had a seminar from Liz Fong-Jones entitled “Reverse engineering hate” about how she, and a dozen colleagues, have been working to take down a hate speech forum called Kiwi Farms. We already published a measurement study of their campaign, which forced the site offline repeatedly in 2022. As a result of that paper, Liz contacted us and this week she told us the inside story.

The forum in question specialises in personal attacks, and many of their targets are transgender. Their tactics include doxxing their victims, trawling their online presence for material that is incriminating or can be misrepresented as such, putting doctored photos online, and making malicious complaints to victims’ employers and landlords. They describe this as “milking people for laughs”. After a transgender activist in Canada was swatted, about a dozen volunteers got together to try to take the site down. They did this by complaining to the site’s service providers and by civil litigation.

This case study is perhaps useful for the UK, where the recent Online Safety Bill empowers Ofcom to do just this – to use injunctions in the civil courts to take down unpleasant websites.

The Kiwi Farms operator has for many months resisted the activists by buying the services required to keep his website up, including his data centre floor space, his transit, his AS, his DNS service and his DDoS protection, through a multitude of changing shell companies. The current takedown mechanisms require a complainant to first contact the site operator; he publishes complaints, so his followers can heap abuse on them. The takedown crew then has to work up a chain of suppliers. Their processes are usually designed to stall complainants, so that getting through to a Tier 1 and getting them to block a link takes weeks rather than days. And this assumes that the takedown crew includes experienced sysadmins who can talk the language of the service providers, to whose technical people they often have direct access; without that, it would take months rather than weeks. The net effect is that it took a dozen volunteers thousands of hours over six months from October 22 to April 23 to get all the Tier 1s to drop KF, and over $100,000 in legal costs. If the bureaucrats at Ofcom are going to do this work for a living, without the skills and access of Liz and her team, it could be harder work than they think.

Liz’s seminar slides are here.

Hacktivism, in Ukraine and Gaza

People who write about cyber-conflict often talk of hacktivists and other civilian volunteers who contribute in various ways to a cause. Might the tools and techniques of cybercrime enable its practitioners to be effective auxiliaries in a real conflict? Might they fall foul of the laws of war, and become unlawful combatants?

We have now measured hacktivism in two wars – in Ukraine and Gaza – and found that its effects appear to be minor and transient in both cases.

In the case of Ukraine, hackers supporting Ukraine attacked Russian websites after the invasion, followed by Russian hackers returning the compliment. The tools they use, such as web defacement and DDoS, can be measured reasonably well using resources we have developed at the Cambridge Cybercrime Centre. The effects were largely trivial, expressing solidarity and sympathy rather than making any persistent contribution to the conflict. Their interest in the conflict dropped off rapidly.

In Gaza, we see the same pattern. After Hamas attacked Israel and Israel declared war, there was a surge of attacks that peaked after a few days, with most targets being strategically unimportant. In both cases, discussion on underground cybercrime forums tailed off after a week. The main difference is that the hacktivism against Israel is one-sided; supporters of Palestine have attacked Israeli websites, but the number of attacks on Palestinian websites has been trivial.

The Pre-play Attack in Real Life

Recently I was contacted by a Falklands veteran who was a victim of what appears to have been a classic pre-play attack; his story is told here.

Almost ten years ago, after we wrote a paper on the pre-play attack, we were contacted by a Scottish sailor who’d bought a drink in a bar in Las Ramblas in Barcelona for €33, and found the following morning that he’d been charged €33,000 instead. The bar had submitted ten transactions an hour apart for €3,300 each, and when we got the transaction logs it turned out that these transactions had been submitted through three different banks. What’s more, although the transactions came from the same terminal ID, they had different terminal characteristics. When the sailor’s lawyer pointed this out to Lloyds Bank, they grudgingly accepted that it had been technical fraud and refunded the money.

In the years since then, I’ve used this as a teaching example both in tutorial talks and in university lectures. A payment card user has no trustworthy user interface, so the PIN entry device can present any transaction, or series of transactions, for authentication, and the customer is none the wiser. The mere fact that a customer’s card authenticated a transaction does not imply that the customer mandated that payment.

Payment by phone should eventually fix this, but meantime the frauds continue. They’re particularly common in nightlife establishments, both here and overseas. In the first big British case, the Spearmint Rhino in Bournemouth had special conditions attached to its license for some time after a series of frauds; a second case affected a similar establishment in Soho; there have been others. Overseas, we’ve seen cases affecting UK cardholders in Poland and the Baltic states. The technical modus operandi can involve a tampered terminal, a man-in-the-middle device or an overlay SIM card.

By now, such attacks are very well-known and there really isn’t any excuse for banks pretending that they don’t exist. Yet, in this case, neither the first responder at Barclays nor the case handler at the Financial Ombudsman Service seemed to understand such frauds at all. Multiple transactions against one cardholder, coming via different merchant accounts, and with delay, should have raised multiple red flags. But the banks have gone back to sleep, repeating the old line that the card was used and the customer PIN was entered, so it must all be the customer’s fault. This is the line they took twenty years ago when chip and pin was first introduced, and indeed thirty years ago when we were suffering ATM fraud at scale from mag-strip copying. The banks have learned nothing, except perhaps that they can often get away with lying about the security of their systems. And the ombudsman continues to claim that it’s independent.

2023 Workshop on the Economics of Information Security

WEIS 2023, the 22nd Workshop on the Economics of Information Security, will be held in Geneva from July 5-7, with a theme of Digital Sovereignty. We now have a list of sixteen accepted papers; there will also be three invited speakers, ten posters, and ten challenges for a Digital Sovereignty Hack on July 7-8.

The deadline for early registration is June 10th, and we have discount hotel bookings reserved until then. As Geneva gets busy in summer, we suggest you reserve your room now!

Security economics course

Back in 2015 I helped record a course in security economics in a project driven by colleagues from Delft. This was launched as an EDX MOOC as well as becoming part of the Delft syllabus, and it has been used in many other courses worldwide. In Brussels, in December, a Ukrainian officer told me they use it in their cyber defence boot camp.

There’s been a lot of progress in security economics over the past seven years; see for example the liveblogs of the workshop on the economics of information security here. So it’s time to update the course, and we’ll be working on that between now and May.

If there are any topics you think we should cover, or any bugs you’d like to report, please get in touch!

Evidence based policing (of booters)

“Booters” (they usually call themselves “stressers” in a vain attempt to appear legitimate) are denial-of-service-for-hire websites where anyone can purchase small scale attacks that will take down a home Internet connection, a High School (perhaps there’s an upcoming maths test?) or a poorly defended business website. Prices vary but for around $20.00 you can purchase as many 10 minute attacks as you wish to send for the next month! In pretty much every jurisdiction, booters are illegal to run and illegal to use, and there have been a series of Law Enforcement take-downs over the years, notably in the US, UK, Israel and the Netherlands.

On Wednesday December 14th, in by far the biggest operation to date, the FBI announced the arrest of six booter operators and the seizure of 49 (misreported as 48) booter domain names. Visiting those domains will now display a “WEBSITE SEIZED” splash page.

FBI website seizure splash page

The seizures were “evidence based” in that the FBI specifically targeted the most active booters by taking advantage of one of the datasets collected by the Cambridge Cybercrime Centre, which uses self-reported data from booters.
Continue reading Evidence based policing (of booters)

Hiring for AP4L

I’m hiring a Research Assistant/Associate to work on the EPSRC-funded Adaptive PETs to Protect & emPower People during Life Transitions (AP4L) project. The project is being undertaken with the Universities of Surrey, Queen Mary, Strathclyde, Edge Hill, and Edinburgh.

AP4L is a program of interdisciplinary research, centring on the online privacy & vulnerability challenges that people face when going through major life transitions. The four transitions we are considering in the scope of this project are relationship breakdowns; LBGT+ transitions or transitioning gender; entering/ leaving employment in the Armed Forces; and developing a serious illness or becoming terminally ill. Our central goal is to develop privacy-by-design technologies to protect & empower people during these transitions.

We are looking for a researcher with experience in quantitative data analysis, threat assessment, data science, machine learning and/or natural language processing, as well as excellent programming and technical writing skills. Expertise in cybercrime or privacy enhancing technologies (PETs) research is desirable, but not essential. Successful applicants will review the relevant literature, design research projects, develop tools, collect and analyse data, and write research outputs.

The role will analyse life transitions from the attacker’s perspective, such as how and where they gather information about their victims. This will require the analysis of cybercrime forums and similar data at scale. Furthermore, the tools we develop are designed for an adversarial context. Adversaries include those known to individuals, such as interfamilial abuse, as well as targeted and indiscriminate attacks. The researcher will also undertake a rigorous threat analysis for each of the tools developed within the overall project.

The full details are available here.

Chatcontrol or Child Protection?

Today I publish a detailed rebuttal to the argument from the intelligence community that we need to break end-to-end encryption in order to protect children. This has led in the UK to the Online Safety Bill and in the EU to the proposed Child Sex Abuse Regulation, which has become known in Brussels as “chatcontrol”.

The intelligence community wants to break WhatsApp, as that carries everything from diplomatic and business negotiations to MPs’ wheeling and dealing. Both the UK and EU proposals will take powers to mandate scanning of both text and images in your phone before messages are encrypted and sent, or after they are received and decrypted.

This is justified with arguments around child protection, which require careful study. Most child abuse happens in dysfunctional families, with the abuser typically being the mother’s partner; technology is often abused as a means of extortion and control. Indecent images get shared with outsiders, and user reports of such images are a really important way of alerting the police to new cases. There are also abusers who look for vulnerable minors online, and here too it’s user reporting that does most of the work.

But it costs money to get moderators to respond to user reports of abuse, so the tech firms’ performance here is unimpressive. Facebook seems to be the best of a bad lot, while Twitter is awful – and so hosts a lot more abuse. There’s a strong case for laws to compel service providers to manage user reporting better, and the EU’s Digital Services Act goes some way in this direction. The Online Safety Bill should be amended to do the same, and we produced a policy paper on this last week.

But details matter, as it’s important to understand the many inappropriate laws, dysfunctional institutions and perverse incentives that get in the way of rational policies around the online aspects of crimes of sexual violence against minors. (The same holds for violent online political extremism, which is also used as an excuse for more censorship and surveillance.) We do indeed need to spend more money on reducing violent crime, but it should be spent locally on hiring more police officers and social workers to deal with family violence directly. We also need welfare reform to reduce the number of families living in poverty.

As for surveillance, it has not helped in the past and there is no real prospect that the measures now proposed would help in the future. I go through the relevant evidence in my paper and conclude that “chatcontrol” will not improve child protection, but damage it instead. It will also undermine human rights at a time when we need to face down authoritarians not just technologically and militarily, but morally as well. What’s the point of this struggle, if not to defend democracy, the rule of law, and human rights?

Edited to add: here is a video of a talk I gave on the paper at Digitalize.