I’m in the Security Protocols Workshop, whose theme this year is “security protocols for humans”. I’ll try to liveblog the talks in followups to this post.
Have you ever wondered whether one app on your phone could spy on what you’re typing into another? We have. Five years ago we showed that you could use the camera to measure the phone’s motion during typing and use that to recover PINs. Then three years ago we showed that you could use interrupt timing to recover text entered using gesture typing. So what other attacks are possible?
Our latest paper shows that one of the apps on the phone can simply record the sound from its microphones and work out from that what you’ve been typing.
Your phone’s screen can be thought of as a drum – a membrane supported at the edges. It makes slightly different sounds depending on where you tap it. Modern phones and tablets typically have two microphones, so you can also measure the time difference of arrival of the sounds. The upshot is that can recover PIN codes and short words given a few measurements, and in some cases even long and complex words. We evaluate the new attack against previous ones and show that the accuracy is sometimes even better, especially against larger devices such as tablets.
This paper is based on Ilia Shumailov’s MPhil thesis project.
I’m at Financial Crypto 2019 and will try to liveblog some of the sessions in followups to this post.
I am at the Symposium on Post-Bitcoin Cryptocurrencies in Vienna and will try to liveblog the talks in follow-ups to this post.
The introduction was by Bernhard Haslhofer of AIT, who maintains the graphsense.info toolkit and runs the Titanium project on bitcoin forensics jointly with Rainer Boehme of Innsbruck. Rainer then presented an economic analysis arguing that criminal transactions were pretty well the only logical app for bitcoin as it’s permissionless and trustless; if you have access to the courts then there are better ways of doing things. However in the post-bitcoin world of ICOs and smart contracts, it’s not just the anti-money-laundering agencies who need to understand cryptocurrency but the securities regulators and the tax collectors. Yet there is a real policy tension. Governments hype blockchains; Austria uses them to auction sovereign bonds. Yet the only way in for the citizen is through the swamp. How can the swamp be drained?
Over the last thirty years or so, we’ve seen security protocols evolving in different ways, at different speeds, and at different levels in the stack. Today’s TLS is much more complex than the early SSL of the mid-1990s; the EMV card-payment protocols we now use at ATMs are much more complex than the ISO 8583 protocols used in the eighties when ATM networking was being developed; and there are similar stories for GSM/3g/4g, SSH and much else.
How do we make sense of all this?
Reconciling Multiple Objectives – Politics or Markets? was particularly inspired by Jan Groenewegen’s model of innovation according to which the rate of change depends on the granularity of change. Can a new protocol be adopted by individuals, or does it need companies to adopt it en masse for internal use, or does it need to spread through a whole ecosystem, or – the hardest case of all – does it require a change in culture, norms or values?
Security engineers tend to neglect such “soft” aspects of engineering, and we probably shouldn’t. So we sketch a model of the innovation stack for security and draw a few lessons.
Perhaps the most overlooked need in security engineering, particularly in the early stages of a system’s evolution, is recourse. Just as early ATM and point-of-sale system operators often turned away fraud victims claiming “Our systems are secure so it must have been your fault”, so nowadays people who suffer abuse on social media can find that there’s nowhere to turn. A prudent engineer should anticipate disputes, and give some thought in advance to how they should be resolved.
Reconciling Multiple Objectives appeared at Security Protocols 2017. I forgot to put the accepted version online and in the repository after the proceedings were published in late 2017. Sorry about that. Fortunately the REF rule that papers must be made open access within three months doesn’t apply to conference proceedings that are a book series; it may be of value to others to know this!
Bitcoin Redux explains what’s going wrong in the world of cryptocurrencies. The bitcoin exchanges are developing into a shadow banking system, which do not give their customers actual bitcoin but rather display a “balance” and allow them to transact with others. However if Alice sends Bob a bitcoin, and they’re both customers of the same exchange, it just adjusts their balances rather than doing anything on the blockchain. This is an e-money service, according to European law, but is the law enforced? Not where it matters. We’ve been looking at the details.
In March we wrote about how to trace stolen bitcoin, describing new tools that enable us to track crime proceeds on the blockchain with more precision than before. We waited for victims of bitcoin theft and fraud to come to us, so we could test our tools on real cases. However in most of them it was not clear that the victims had ever owned any bitcoin at all.
There are basically three ways you could try to hold a bitcoin. You could buy one from an exchange and get them to send it to a wallet you host yourself, but almost nobody does that.
You could buy one from an exchange and get the exchange to keep the keys for you, so that the asset was unique to you and they were only guarding it for you – just like when you buy gold and the bullion merchant then charges you a fee to guard your gold in his vault. If the merchant goes bust, you can turn up at the vault with your receipt and demand your gold back.
Or you could buy one from an exchange and have them owe you a bitcoin – just as when you put your money in the bank. The bank doesn’t have a stack of banknotes in the vault with your name on it; and if it goes bust you have to stand in line with the other creditors.
It seems that most people who buy bitcoin think that they’re operating under the gold merchant model, while most exchanges operate under the bank model. This raises a whole host of issues around solvency, liquidity, accounting practices, money laundering, risk and trust. The details matter, and the more we look at them, the worse it seems.
This paper will appear at the Workshop on the Economics of Information Security later this month. It contains eight recommendations for what governments should be doing to clean up this mess.
I’m at Financial Crypto 2018 and will try to liveblog some of the sessions in followups to this post.
This week brought an announcement from a banking association that “identity fraud” is soaring to new levels, with 89,000 cases reported in the first six months of 2017 and 56% of all fraud reported by its members now classed as “identity fraud”.
So what is “identity fraud”? The announcement helpfully clarifies the concept:
“The vast majority of identity fraud happens when a fraudster pretends to be an innocent individual to buy a product or take out a loan in their name. Often victims do not even realise that they have been targeted until a bill arrives for something they did not buy or they experience problems with their credit rating. To carry out this kind of fraud successfully, fraudsters need access to their victim’s personal information such as name, date of birth, address, their bank and who they hold accounts with. Fraudsters get hold of this in a variety of ways, from stealing mail through to hacking; obtaining data on the ‘dark web’; exploiting personal information on social media, or though ‘social engineering’ where innocent parties are persuaded to give up personal information to someone pretending to be from their bank, the police or a trusted retailer.”
Now back when I worked in banking, if someone went to Barclays, pretended to be me, borrowed £10,000 and legged it, that was “impersonation”, and it was the bank’s money that had been stolen, not my identity. How did things change?
The members of this association are banks and credit card issuers. In their narrative, those impersonated are treated as targets, when the targets are actually those banks on whom the impersonation is practised. This is a precursor to refusing bank customers a “remedy” for “their loss” because “they failed to protect themselves.”
Now “dishonestly making a false representation” is an offence under s2 Fraud Act 2006. Yet what is the police response?
The Head of the City of London Police’s Economic Crime Directorate does not see the banks’ narrative as dishonest. Instead he goes along with it: “It has become normal for people to publish personal details about themselves on social media and on other online platforms which makes it easier than ever for a fraudster to steal someone’s identity.” He continues: “Be careful who you give your information to, always consider whether it is necessary to part with those details.” This is reinforced with a link to a police website with supposedly scary statistics: 55% of people use open public wifi and 40% of people don’t have antivirus software (like many security researchers, I’m guilty on both counts). This police website has a quote from the Head’s own boss, a Commander who is the National Police Coordinator for Economic Crime.
How are we to rate their conduct? Given that the costs of the City force’s Dedicated Card and Payment Crime Unit are borne by the banks, perhaps they feel obliged to sing from the banks’ hymn sheet. Just as the MacPherson report criticised the Met for being institutionally racist, we might perhaps describe the City force as institutionally corrupt. There is a wide literature on regulatory capture, and many other examples of regulators keen to do the banks’ bidding. And it’s not just the City force. There are disgraceful examples of the Metropolitan Police Commissioner and GCHQ endorsing the banks’ false narrative. However people are starting to notice, including the National Audit Office.
Or perhaps the police are just clueless?
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
The National Audit Office has found as follows:
“For too long, as a low value but high volume crime, online fraud has been overlooked by government, law enforcement and industry. It is now the most commonly experienced crime in England and Wales and demands an urgent response. While the Department is not solely responsible for reducing and preventing online fraud, it is the only body that can oversee the system and lead change. The launch of the Joint Fraud Taskforce in February 2016 was a positive step, but there is still much work to be done. At this stage it is hard to judge that the response to online fraud is proportionate, efficient or effective.”
Our regular readers will recall that over ten years ago the government got the banks to agree with the police that fraud would be reported to the bank first. This ensured that the police and the government could boast of falling fraud figures, while the banks could direct such fraud investigations as did happen. This was roundly criticized by the Science and Technology Committee (here and here) but the government held firm. Over the succeeding decade, dissident criminologists started pointing out that fraud was not falling, just going online like everything else, and the online stuff was being ignored. Successive governments just didn’t want to know; for most of the period in question the Home Secretary was one Theresa May, who so impressed her party by “cutting crime” even though she’d cut 20,000 police jobs that she got a promotion.
But pigeons come home to roost eventually, and over the last two years the Office of National Statistics has been moving to more honest crime figures. The NAO report bears close study by anyone interested in cybercrime, in crime generally, and in how politicians game the crime figures. It makes clear that the Home Office doesn’t know what’s going on (or doesn’t really want to) and hopes that other people (such as banks and the IT industry) will solve the problem.
Government has made one or two token gestures such as setting up Action Fraud, and the NAO piously hopes that the latest such (the Joint Fraud Taskforce) could be beefed up to do some good.
I’m afraid that the NAO’s recommendations are less impressive. Let me give an example. The main online fraud bothering Cambridge University relates to bogus accommodation; about fifty times a year, a new employee or research student turns up to find that the apartment they rented doesn’t exist. This is an organised scam, run by crooks in Germany, that affects students elsewhere in the UK (mostly in London) and is netting £5-10m a year. The cybercrime guy in the Cambridgeshire Constabulary can’t do anything about this as only the National Crime Agency in London is allowed to talk to the German police; but he can’t talk to the NCA directly. He has to go through the Regional Organised Crime Unit in Bedford, who don’t care. The NCA would rather do sexier stuff; they seem to have planned to take over the Serious Fraud Office, as that was in the Conservative manifesto for this year’s election.
Every time we look at why some scam persists, it’s down to the institutional economics – to the way that government and the police forces have arranged their targets, their responsibilities and their reporting lines so as to make problems into somebody else’s problems. The same applies in the private sector; if you complain about fraud on your bank account the bank may simply reply that as their systems are secure, it’s your fault. If they record it at all, it may be as a fraud you attempted to commit against them. And it’s remarkable how high a proportion of people prosecuted under the Computer Misuse Act appear to have annoyed authority, for example by hacking police websites. Why do we civilians not get protected with this level of enthusiasm?
Many people have lobbied for change; LBT readers will recall numerous articles over the last ten years. Which? made a supercomplaint to the Payment Services Regulator, and got the usual bland non-reassurance. Other members of the old establishment were less courteous; the Commissioner of the Met said that fraud was the victims’ fault and GCHQ agreed. Such attitudes hit the poor and minorities the hardest.
The NAO is just as reluctant to engage. At p34 it says of the Home Office “The Department … has to influence partners to take responsibility in the absence of more formal legal or contractual levers.” But we already have the Payment Services Regulations; the FCA explained in response to the Tesco Bank hack that the banks it regulates should make fraud victims good. And it has always been the common-law position that in the absence of gross negligence a banker could not debit his customer’s account without the customer’s mandate. What’s lacking is enforcement. Nobody, from the Home Office through the FCA to the NAO, seems to want to face down the banks. Rather than insisting that they obey the law, the Home Office will spend another £500,000 on a publicity campaign, no doubt to tell us that it’s all our fault really.