All posts by Ross Anderson

FC 2020

I’m at Financial Cryptography 2020 and will try to liveblog some of the talks in followups to this post.

The keynote was given by Allison Nixon, Chief Research Officer of Unit221B, on “Fraudsters Taught Us that Identity is Broken”.

Allison started by showing the Mitchell and Webb clip. In a world where even Jack Dorsey got his twitter hacked via incoming SMS, what is identity? Your thief becomes you. Abuse of old-fashioned passports was rare as they were protected by law; now they’re your email address (which you got by lying to an ad-driven website) and phone number (which gets taken away and given to a random person if you don’t pay your bill). If lucky you might have a signing key (generated on a general purpose computer, and hard to revoke – that’s what bitcoin theft is often about). The whole underlying system is wrong. Email domains, like phone numbers, lapse if you forget to pay your bill; fraudsters actively look for custom domains and check if yours has lapsed, while relying parties mostly don’t. Privacy regulations in most countries prevent you from looking up names from phone numbers; many have phone numbers owned by their employers. Your email address can be frozen or removed because of spam if you’re bad or are hacked, while even felons are not deprived of their names. Evolution is not an intelligent process! People audit password length but rarely the password reset policy: many use zero-factor auth, meaning information that’s sort-of public like your SSN. In Twitter you reset your password then message customer support asking them to remove two-factor, and they do, so long as you can log on! This is a business necessity as too many people lose their phone or second factor, so this customer-support backdoor will never be properly closed. Many bitcoin exchanges have no probation period, whether mandatory or customer option. SIM swap means account theft so long as phone number enables password reset – she also calls this zero-factor authentication.

SIM swap is targeted, unlike most password-stuffing attacks, and compromises people who comply with all the security rules. Allison tried hard to protect herself against this fraud but mostly couldn’t as the phone carrier is the target. This can involve data breaches at the carrier, insider involvement and the customer service back door. Email domain abuse is similar; domain registrars are hacked or taken over. Again, the assumptions made about the underlying infrastructure are wrong. Your email can be reset by your phone number and vice versa. Your private key can be stolen via your cloud backups. Both identity vendors and verifiers rely on unvetted third parties; vendors can’t notify verifiers of a hack. The system failure is highlighted by the existence of criminal markets in identity.

There are unrealistic expectations too. As a user of a general-purpose computer, you have no way to determine whether your machine is suitable for storing private keys, and almost 100% of people are unable to comply with security advice. That tells you it’s the system that’s broken. It’s a blame game, and security advice is as much cargo cult as anything else.

What would a better identity system look like? There would be an end to ever-changing advice; you’d be notified if your information got stolen, just as you know if your physical driving license is stolen; there would be an end to unreasonable expectations of both humans and computers; the legal owner of the identity would be the person identified and would be non-transferable and irrevocable; it would not depend on the integrity of 3rd-party systems like DNS and CAs and patch management mechanisms; we’ll know we’re there once the criminal marketplace vanishes.

Questions: What might we do about certificate revocation? A probation period is the next thing to do, as how people learn of a SIM swap is a flood of password reset messages in email, and then it’s a race. I asked whether rather than fixing the whole world, we should fix it one relying party at a time? Banks give you physical tokens after all, as they’re regulated and have to eat the losses. Allison agreed; in 2019 she talked about SIM swap to many banks but had no interest from any crypto exchange. Curiously, the lawsuits tend to target carriers rather than the exchanges. What about SS7? There are sophisticated Russian criminal gangs doing such attacks, but they require a privileged position in the network, like BGP attacks. What about single signon? The market is currently in flux and might eventually settle on a few vendors. What about SMS spoofing attacks? Allison hasn’t seen them in 4g marketplaces or in widespread criminal use. Caller-ID spoofing is definitely used, by bad guys who organise SWATting. Should we enforce authentication tokens? The customer service department will be inundated with people who have lost theirs and that will become the backdoor. Would blockchains help? No, they’re just an audit log, and the failures are upstream. The social aspect is crucial: people know how to protect their physical cash in their wallet, and a proper solution to the identity problem must work like that. It’s not an impossible task, and might involve a chip in your driver’s license. It’s mostly about getting the execution right.

Security Engineering, and Sustainability

Yesterday I got the audience at the 36th Chaos Computer Congress in Leipzig to vote on the cover art for the third edition of my textbook on Security Engineering: you can see the result here.

It was a privilege to give a talk at 36C3; as the theme was sustainability, I spoke on The Sustainability of Safety, Security and Privacy. This is a topic on which I’ve written and spoken several times in recent years, but we now have some progress to report. The EU has changed the rules to require that if you sell goods with digital components (whether embedded software, associated cloud services or smartphone apps) then these have to be maintained for as long as the customer might reasonably expect.

2020 Caspar Bowden Award

You are invited to submit nominations for the 2020 Caspar Bowden Award for Outstanding Research in Privacy Enhancing Technologies. The Caspar Bowden PET award is presented annually to researchers who have made an outstanding contribution to the theory, design, implementation, or deployment of privacy enhancing technology. It is awarded at the annual Privacy Enhancing Technologies Symposium (PETS), and carries a cash prize as well as a physical award monument.

Any paper by any author written in the area of privacy enhancing technologies is eligible for nomination. However, the paper must have appeared in a refereed journal, conference, or workshop with proceedings published in the period from April 1, 2018 until March 31, 2020.

Note that we do not accept nominations for publications in conference proceedings when the dates of the conference fall outside of the nomination window. For example, a IEEE Symposium on Security and Privacy (“Oakland”) paper made available on IEEE Xplore prior to the March 31 deadline would not be eligible, as the conference happens in May. Please note that PETS is associated with a journal publication, PoPETs, so any PoPETs paper published in an issue appearing before the March 31 deadline is eligible (which typically means only Issue 1 of the current year).

Anyone can nominate a paper by sending an email message to award-chairs20@petsymposium.org containing the following:
. Paper title
. Author(s)
. Author(s) contact information
. Publication venue and full reference
. Link to an available online version of the paper
. A nomination statement of no more than 500 words.

All nominations must be submitted by April 5, 2020. The award committee will select one or two winners among the nominations received. Winners must be present at the PET Symposium in order to receive the Award. This requirement can be waived only at the discretion of the PET advisory board. The complete Award rules including eligibility requirements can be found here.

Caspar Bowden PET Award Chairs (award-chairs20@petsymposium.org)

Simone Fischer-Hübner, Karlstad University
Ross Anderson, University of Cambridge

Caspar Bowden PET Award Committee

Erman Ayday, Bilkent University
Nataliia Bielova, Inria
Sonja Buchegger, KTH
Ian Goldberg, University of Waterloo
Rachel Greenstadt, NYU
Marit Hansen, Unabhängiges Datenschutzzentrum Schleswig Holstein -ULD
Dali Kaafar, CSIRO
Eran Toch, Tel Aviv University
Carmela Troncoso, EPFL
Matthew Wright, Rochester Institute of Technology

More information about the Caspar Bowden PET award (including past winners) is available here.

Rental scams

One of the cybercrimes that bothers us at Cambridge is accommodation fraud. Every October about 1% the people who come as grad students or postdocs rent an apartment that just doesn’t exist. Sites like Craigslist are full of ads that are just too good to be true. While the university does what it can to advise new hires and admissions to use our own accommodation services if they cannot check out an apartment personally, perhaps 50 new arrivals still turn up to find that they have nowhere to live, their money is gone, and the police aren’t interested. This is not a nice way to start your PhD.

Some years ago a new postdoc, Sophie van der Zee, almost fell for such a scam, and then got to know someone here who had actually become a victim. She made this into a research project, and replied to about a thousand scam ads. We analysed the persuasion techniques that the crooks used.

Here at last is our analysis: The gift of the gab: Are rental scammers skilled at the arts of persuasion? We found that most of the techniques the scammers used are straight from the standard marketing textbook (Cialdini) rather than from the lists of more exotic scam techniques compiled by fraud researchers such as Stajano and Wilson. The only significant exception was appeals to sympathy. Most of the scammers were operating out of West Africa in what appears to have one or more boilerhouse sales operations. They work from scripts, very much like people selling insurance or home improvements.

Previous cybercrime research looked at both high-value targeted operations and scale attackers who compromise machines in bulk. This is an example of fraud lying between the “first class” and “economy class” versions of cybercrime.

Rental scams are still a problem for new staff and students. Since this work was done, things have changed somewhat, in that most of the scams are now run by an operator using slick websites who, according to the local police, appears to be based in Germany. We have repeatedly tried, and failed, to persuade the police (local and Met), the NCA and the NCSC to have his door broken down. Unfortunately the British authorities appear to lack the motivation to extradite foreigners who commit small frauds at scale. So if you want to steal a few million a year, take it from a few thousand people, a thousand pounds at a time. So long as you stay overseas there seems to be little risk of arrest.

SHB 2019 – Liveblog

I’ll be trying to liveblog the twelfth workshop on security and human behaviour at Harvard. I’m doing this remotely because of US visa issues, as I did for WEIS 2019 over the last couple of days. Ben Collier is attending as my proxy and we’re trying to build on the experience of telepresence reported here and here. My summaries of the workshop sessions will appear as followups to this post.

WEIS 2019 – Liveblog

I’ll be trying to liveblog the seventeenth workshop on the economics of information security at Harvard. I’m not in Cambridge, Massachussetts, but in Cambridge, England, because of a visa held in ‘administrative processing’ (a fate that has befallen several other cryptographers). My postdoc Ben Collier is attending as my proxy (inspired by this and this).

The Changing Cost of Cybercrime

In 2012 we presented the first systematic study of the costs of cybercrime. We have now repeated our study, to work out what’s changed in the seven years since then.

Measuring the Changing Cost of Cybercrime will appear on Monday at WEIS. The period has seen huge changes, with the smartphone replacing as PC and laptop as the consumer terminal of choice, with Android replacing Windows as the most popular operating system, and many services moving to the cloud. Yet the overall pattern of cybercrime is much the same.

We know a lot more than we did then. Back in 2012, we guessed that cybercrime was about half of all crime, by volume and value; we now know from surveys in several countries that this is the case. Payment fraud has doubled, but fallen slightly as a proportion of payment value; the payment system has got larger, and slightly more efficient.

So what’s changed? New cybercrimes include ransomware and other offences related to cryptocurrencies; travel fraud has also grown. Business email compromise and its cousin, authorised push payment fraud, are also growth areas. We’ve also seen serious collateral damage from cyber-weapons such as the NotPetya worm. The good news is that crimes that infringe intellectual property – from patent-infringing pharmaceuticals to copyright-infringing software, music and video – are down.

Our conclusions are much the same as in 2012. Most cyber-criminals operate with impunity, and we have to fix this. We need to put a lot more effort into catching and punishing the perpetrators.

Our new paper is here. For comparison the 2012 paper is here, while a separate study on the emotional cost of cybercrime is here.

Security Engineering: Third Edition

I’m writing a third edition of my best-selling book Security Engineering. The chapters will be available online for review and feedback as I write them.

Today I put online a chapter on Who is the Opponent, which draws together what we learned from Snowden and others about the capabilities of state actors, together with what we’ve learned about cybercrime actors as a result of running the Cambridge Cybercrime Centre. Isn’t it odd that almost six years after Snowden, nobody’s tried to pull together what we learned into a coherent summary?

There’s also a chapter on Surveillance or Privacy which looks at policy. What’s the privacy landscape now, and what might we expect from the tussles over data retention, government backdoors and censorship more generally?

There’s also a preface to the third edition.

As the chapters come out for review, they will appear on my book page, so you can give me comment and feedback as I write them. This collaborative authorship approach is inspired by the late David MacKay. I’d suggest you bookmark my book page and come back every couple of weeks for the latest instalment!