Evidence Critical Systems: Designing for Dispute Resolution

On Friday, 39 subpostmasters had their criminal convictions overturned by the Court of Appeal. These individuals ran post office branches and were prosecuted for theft, fraud and false accounting based on evidence from Horizon, the Post Office computer system created by Fujitsu. Horizon’s evidence was asserted to be reliable by the Post Office, who mounted these prosecutions, and was accepted as proof by the courts for decades. It was only through a long and expensive court case that a true record of Horizon’s problems became publicly known, with the judge concluding that it was “not remotely reliable”, and so allowing these successful appeals against conviction.

The 39 quashed convictions are only the tip of the iceberg. More than 900 subpostmasters were prosecuted based on evidence from Horizon, and many more were forced to reimburse the Post Office for losses that might never have existed. It could be the largest miscarriage of justice the UK has ever seen, and at the centre is the Horizon computer system. The causes of this failure are complex, but one of the most critical is that neither the Post Office nor Fujitsu disclosed the information necessary to establish the reliability (or lack thereof) of Horizon to subpostmasters disputing its evidence. Their reasons for not doing so include that it would be expensive to collect the information, that the details of the system are confidential, and disclosing the information would harm their ability to conduct future prosecutions.

The judgment quashing the convictions had harsh words about this failure of disclosure, but this doesn’t get away from the fact that over 900 prosecutions took place before the problem was identified. There could easily have been more. Similar questions have been raised relating to payment disputes: when a customer claims to be the victim of fraud but the bank says it’s the customer’s fault, could a computer failure be the cause? Both the Post Office and banking industry rely on the legal presumption in England and Wales that computers operate correctly. The responsibility for showing otherwise is for the subpostmaster or banking customer.

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Still treating users as the enemy: entrapment and the escalating nastiness of simulated phishing campaigns

Three years ago, we made the case against phishing your own employees through simulated phishing campaigns. They do little to improve security: click rates tend to be reduced (temporarily) but not to zero – and each remaining click can enable an attack. They also have a hidden cost in terms of productivity – employees have to spend time processing more emails that are not relevant to their work, and then spend more time pondering whether to act on emails. In a recent paper, Melanie Volkamer and colleagues provided a detailed listing of the pros and cons from the perspectives of security, human factors and law. One of the legal risks was finding yourself in court with one of the 600-pound digital enterprise gorillas for trademark infringement – Facebook objected to their trademark and domain being impersonated. They also likely don’t want their brand to be used in attacks because, contrary to what some vendors tell you, being tricked by your employer is not a pleasant experience. Negative emotions experienced with an event often transfer to anyone or anything associated with it – and negative emotions are not what you want associated with your brand if your business depends on keeping billions of users engaging with your services as often as possible.

Recent tactics employed by the providers of phishing campaigns can only be described as entrapment – to “demonstrate” the need for their services, they create messages that almost everyone will click on. Employees of the Chicago Tribune and GoDaddy, for instance, received emails promising bonuses. Employees had hope of extra pay raised and then cruelly dashed, and on top, were hectored for being careless about phishing. Some employees vented their rage publicly on Twitter, and the companies involved apologised. The negative publicity may eventually be forgotten, but the resentment of employees feeling not only tricked but humiliated and betrayed, will not fade any time soon. The increasing nastiness of entrapment has seen employees targeted with promises of COVID vaccinations from employers – who then find themselves being ridiculed for their gullibility instead of lauded for their willingness to help.

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Thoughts on the Future Implications of Microsoft’s Legal Approach towards the TrickBot Takedown

Just this week, Microsoft announced its takedown operation against the TrickBot botnet, in collaboration with other cybersecurity partners, such as FS-ISAC, ESET, and Symantec. This takedown followed Microsoft’s successful application for a court order this month, enabling them to enact technical disruption against the botnet. Such legal processes are typical and necessary precursors to such counter-operations.

However, what was of particular interest, in this case, was the legal precedent Microsoft (successfully) sought, which was based on breaches of copyright law. Specifically, they founded their claim on the alleged reuse (and misuse) of Microsoft’s copyrighted software – the Windows 8 SDK – by the TrickBot malware authors.

Now, it is clear that this takedown operation is not likely to cripple the entirety of the TrickBot operation. As numerous researchers have found (e.g., Stone-Gross et al., 2011; Edwards et al., 2015), a takedown operation often works well in the short-term, but the long-term effects are highly variable. More often than not, unless they are arrested, and their infrastructure is seized, botnet operators tend to respond to such counter-operations by redeploying their infrastructure to new servers and ISPs, moving their operations to other geographic regions or new targets, and/or adapting their malware to become more resistant to detection and analysis. In fact, these are just some of the behaviours we observed in a case-by-case longitudinal study on botnets targeted by law enforcement (one of which involved Dyre, a predecessor of the TrickBot malware). A pre-print of this study is soon to be released.

So, no, I’m not proposing to discuss the long-term efficacy of takedown operations such as this. That is for another blog post.

Rather, what I want to discuss (or, perhaps, more accurately, put forward as some initial thoughts) are the potential implications of Microsoft’s legal approach to obtaining the court order (which is incumbent for such operations) on future botnet takedowns, particularly in the area of malicious code reuse.

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Consider unintended harms of cybersecurity controls, as they might harm the people you are trying to protect

Well-meaning cybersecurity risk owners will deploy countermeasures in an effort to manage the risks they see affecting their services or systems. What is not often considered is that those countermeasures may produce unintended, negative consequences themselves. These unintended consequences can potentially be harmful, adversely affecting user behaviour, user inclusion, or the infrastructure itself (including services of others).

Here, I describe a framework co-developed with several international researchers at a Dagstuhl seminar in mid-2019, resulting in an eCrime 2019 paper later in the year. We were drawn together by an interest in understanding unintended harms of cybersecurity countermeasures, and encouraging efforts to preemptively identify and avoid these harms. Our collaboration on this theme drew on our varied and multidisciplinary backgrounds and interests, including not only risk management and cybercrime, but also security usability, systems engineering, and security economics.

We saw it as necessary to focus on situations where there is often an urgency to counter threats, but where efforts to manage threats have the potential to introduce harms. As documented in the recently published seminar report, we explored specific situations in which potential harms may make resolving the overarching problems more difficult, and as such cannot be ignored – especially where potentially harmful countermeasures ought to be avoided. Example case studies of particular importance include tech-abuse by an intimate partner, online disinformation campaigns, combating CEO fraud and phishing emails in organisations, and online dating fraud.

Consider disinformation campaigns, for example. Efforts to counter disinformation on social media platforms can include fact-checking and automated detection algorithms behind the scenes. These can reduce the burden on users to address the problem. However, automation can also reduce users’ scepticism towards the information they see; fact-checking can be appropriated as a tool by any one group to challenge viewpoints of dissimilar groups.

We then see how unintended harms can shift the burden of managing cybersecurity to others in the ecosystem without them necessarily expecting it or being prepared for it. There can be vulnerable populations which are disadvantaged by the effects of a control more than others. An example may be legitimate users of social media who are removed – or have their content removed – from a platform, due to traits shared with malicious actors or behaviour, e.g., referring to some of the same topics, irrespective of sentiment – an example of ‘Misclassification’, in the list below. If a user, user group, or their online activity are removed from the system, the risk owner for that system may not notice that problems have been created for users in this way – they simply will not see them, as their actions have excluded them. Anticipating and avoiding unintended harms is then crucial before any such outcomes can occur.

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We’re fighting the good fight, but are we making full use of the armoury?

In this post, we reflect on the current state of cybersecurity and the fight against cybercrime, and identify, we believe, one of the most significant drawbacks Information Security is facing. We argue that what is needed is a new, complementary research direction towards improving systems security and cybercrime mitigation, which combines the technical knowledge and insights gained from Information Security with the theoretical models and systematic frameworks from Environmental Criminology. For the full details, you can read our paper – “Bridging Information Security and Environmental Criminology Research to Better Mitigate Cybercrime.”

The fight against cybercrime is a long and arduous one. Not a day goes by without us hearing (at an increasingly alarming rate) the latest flurry of cyber attacks, malware operations, (not so) newly discovered vulnerabilities being exploited, and the odd sprinkling of a high-profile victim or a widely-used service being compromised by cybercriminals.

A burden borne for too long?

Today, the topic of security and cybercrime is one that is prominent in a number of circles and fields of research (e.g., crime science and criminology, law, sociology, economics, policy, policing), not to talk of wider society. However, for the best part of the last half-century, the burden of understanding and mitigating cybercrime, and improving systems security has been predominantly borne by information security researchers and computer engineers. Of course, this is entirely reasonable. As circumstances had long dictated, the exponential penetration and growth in the capability of digital technologies co-dependently brought the opportunity for malicious exploitation, and, alongside it, the need to combat and prevent such malicious activities. Enter the arms race.

However, and potentially the biggest downside to holding this solitary responsibility for so long, the traditional, InfoSec approach to security and cybercrime prevention has leaned heavily towards the technical side of this mantle: discovering vulnerabilities, creating patches, redefining secure software design (e.g., STRIDE), conceptualising threat models for technical systems, and developing technologies to detect, prevent, and/or counter these threats. But, with the threat landscape of today, is this enough?

Taking stock

Make no mistake, it is clear that such technical skill-sets and innovations that abound and are produced from information security are invaluable in keeping up with similarly skilled and innovative cybercriminals. Unfortunately, however, one may find that such approaches to security and preventing cybercrime are generally applied in an ad hoc manner and lacking systemic structure, with, on the other hand, focus being constantly drawn towards the “top” vulnerabilities (e.g., OWASP’s Top 10) as opposed to “less important” ones (which are just as capable in enabling a compromise), or focus on the most recent wave of cyber threats as opposed to those only occurring a few years ago (e.g., the Mirai botnet and its variants, which have been active as far back as 2016, but are seemingly now on the back burner of priorities).

How much thought, can we say, is being directed towards understanding the operational aspects of cybercrime – the journey of the cybercriminal, so to speak, and their opportunity framework? Patching vulnerabilities and taking down botnets are indeed important, but how much attention is placed on understanding criminal displacement and adaptation: the shift of criminal activity from one form to another, or the adaptation of cybercriminals (and even the victims, targets, and other stakeholders), in reaction to new countermeasures? Are system designers taking the necessary steps to minimise the attack surfaces effectively, considering all techniques available to them? Is it enough to look a problem at face value, develop a state-of-the-art detection system, and move on to the next one? We believe much more can and should be done.

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UK Parliament on protecting consumers from economic crime

On Friday, the UK House of Commons Treasury Committee published their report on the consumer perspective of economic crime. I’ve frequently addressed this topic in my research, as well as here on Bentham’s Gaze, so I’m pleased to see several recommendations of the committee match what myself and colleagues have proposed. In other respects, the report could have gone further, so as well as discussing the positive aspects of the report, I would also like to suggest what more could be done to reduce economic crime and protect its victims.

Irrevocable payments are the wrong default

Transfers between UK bank accounts will generally use the Faster Payment System (FPS), where money will immediately show up in the recipient account. FPS transfers cannot be revoked, even in the case of fraud. This characteristic protects banks because if fraudulently obtained funds leave the banking system, the bank receiving the transfer has no obligation to reimburse the victim.

In contrast, the clearing system for paper cheques permits payments to be revoked for a few days after the funds appeared in the recipient account, should there have been a fraud. This period allows customers to quickly make use of funds they receive, while still giving a window of opportunity for banks and customers to identify and prevent fraud. There’s no reason why this same revocation window could not be applied to fully electronic payment systems like FPS.

In my submissions to consultations on how to prevent push payment scams, I argued that irrevocable payments are the wrong default, and transfers should be possible to reverse in cases of fraud. The same argument applies to consumer-oriented cryptocurrencies like Libra. I’m pleased to see that the Treasury Committee agrees and they have recommended that when a customer sends money to an account for the first time, that transfer be revocable for 24 hours.

Introducing Confirmation of Payee, finally

The banking industry has been planning on launching the Confirmation of Payee system to check if the name of the recipient of a transfer matches what the customer sending money thinks. The committee is clearly frustrated with delays on deploying this system, first promised for September 2018 but since slipped to March 2020. Confirmation of Payee will be a helpful tool for customers to help avoid certain frauds. Still, I’m pleased the committee also recognise it’s limitations and that the “onus will always be on financial firms to develop further methods and technologies to keep up with fraudsters.” It is for this reason that I argued that a bank showing a customer a Confirmation of Payee mismatch should not be a sufficient condition to hold customers liable for fraud, and the push-payment scam reimbursement scheme is wrong to do so. It doesn’t look like the committee is asking for the situation to be changed though.

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A Reflection on the Waves Of Malice: Malicious File Distribution on the Web (part 2)

The first part of this article introduced the malicious file download dataset and the delivery network structure. This final part explores the types of files delivered, discusses how the network varies over time, and concludes with challenges for the research community.

The Great Divide: A PUP Ecosystem and a Malware Ecosystem

We found a notable divide in the delivery of PUP and malware. First, there is much more PUP than malware in the wild: we found PUP-to-malware ratios of 5:1 by number of SHA-2s, and 17:2 by number of raw downloads. Second, we found that mixed delivery mechanisms of PUP and malware are not uncommon (e.g., see our Opencandy case study in the paper). Third, the highly connected Giant Component is predominantly a PUP Ecosystem (8:1 PUP-to-malware by number of SHA-2s), while the many “islands” of download activity outside of this component are predominantly a Malware Ecosystem (1.78:1 malware-to-PUP by number of SHA-2s).

Comparing the structures of the two ecosystems,we found that the PUP Ecosystem leverages a higher degree of IP address and autonomous system (AS) usage per domain and per dropper than the Malware Ecosystem, possibly indicating higher CDN usage or the use of evasive fast-flux techniques to change IP addresses (though, given earlier results, the former is the more likely). On the other hand, the Malware Ecosystem was attributed with fewer SHA-2s being delivered per domain than the PUP Ecosystem with the overall numbers in raw downloads remaining the same, which could again be indicative of a disparity in the use of CDNs between the two ecosystems (i.e., CDNs typically deliver a wide range of content). At the same time, fewer suspicious SHA-2s being delivered per domain could also be attributable to evasive techniques being employed (e.g., malicious sites delivering a few types of files before changing domain) or distributors in this ecosystem dealing with fewer clients and smaller operations.

We tried to estimate the number of PPIs in the wild by defining a PPI service as a network-only component (or group of components aggregated by e2LD) that delivered more than one type of malware or PUP family. Using this heuristic, we estimated a lower bound of 394 PPIs operating on the day, 215 of which were in the PUP Ecosystem. In terms of proportions, we found that the largest, individual PPIs in the PUP and Malware Ecosystems involved about 99% and 24% of all e2LDs and IPs in their ecosystems, respectively.

With there being a number of possible explanations for these structural differences between ecosystems, and such a high degree of potential PPI usage in the wild (especially within the PUP Ecosystem), this is clearly an area in which further research is required.

Keeping Track of the Waves

The final part of the study involved tracking these infrastructures and their activities over time. Firstly, we generated tracking signatures of the network-only (server-side) and file-only (client-side) delivery infrastructures. In essence, this involved tracking the root and trunk nodes in a component, which typically had the highest node degrees, and thus, were more likely to be stable, as opposed to the leaf nodes, which were more likely to be ephemeral.

Continue reading A Reflection on the Waves Of Malice: Malicious File Distribution on the Web (part 2)

A Reflection on the Waves Of Malice: Malicious File Distribution on the Web (part 1)

The French cybercrime unit, C3N, along with the FBI and Avast, recently took down the Retadup botnet that infected more than 850,000 computers, mostly in South America. Though this takedown operation was successful, the botnet was created as early as 2016, with the operators reportedly making millions of euros since. It is clear that large-scale analysis, monitoring, and detection of malicious downloads and botnet activity, even as far back as 2016, is still highly relevant today in the ongoing battle against increasingly sophisticated cybercriminals.

Malware delivery has undergone an impressive evolution since its inception in the 1980s, moving from being an amateur endeavor to a well-oiled criminal business. Delivery methods have evolved from the human-centric transfer of physical media (e.g., floppy disks), sending of malicious emails, and social engineering, to the automated delivery mechanisms of drive-by downloads (malicious code execution on websites and web advertisements), packaged exploit kits (software packages that fingerprint user browsers for specific exploits to maximise the coverage of potential victims), and pay-per-install (PPI) schemes (botnets that are rented out to other cybercriminals).

Furthermore, in recent times, researchers have uncovered the parallel economy of potentially unwanted programs (PUP), which share many traits with the malware ecosystem (such as their delivery through social engineering and PPI networks), while being primarily controlled by different actors. However with some types of PUP, including adware and spyware, PUP has generally been regarded as an annoyance rather than a direct threat to security.

Using the download metadata of millions of users worldwide from 2015/16, we (Colin C. Ife, Yun Shen, Steven J. Murdoch, Gianluca Stringhini) carried out a comprehensive measurement study in the short-term (a 24-hour period), the medium-term (daily, over the course of a month), and the long-term (weekly, over the course of a year) to characterise the structure of this complex malicious file delivery ecosystem on the Web, and how it evolves over time. This work provides us with answers to some key questions, while, at the same time, posing some more and exemplifying some significant issues that continue to hinder security research on unwanted software activity.

An Overview

There were three main research questions that influenced this study, which we will traverse in the following sections of this post:

    1. What does the malicious file delivery ecosystem look like?
    2. How do the networks that deliver only malware, only PUP, or both compare in structure?
    3. How do these file delivery infrastructures and their activities change over time?

For full technical details, you can refer to our paper – Waves of Malice: A Longitudinal Measurement of the Malicious File Delivery Ecosystem on the Web – published by and presented at the ACM AsiaCCS 2019 conference.

The Data

The dataset was provided (and pre-sanitized) by Symantec and consisted of 129 million download events generated by 12 million users. Each download event contained information such as the timestamp, the SHA-2s of the downloaded file and its parent file, the filename, the size (in bytes), the referrer URL, Host URLs (landing pages after redirection) of the download and parent file, and the IP address hosting the download.

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Beyond Regulators’ Concerns, Facebook’s Libra Cryptocurrency Faces another Big Challenge: The Risk of Fraud

Facebook has attracted attention through the announcement of their blockchain-based payment network, Libra. This won’t be the first payment system Facebook has launched, but what makes Facebook’s Libra distinctive is that rather than transferring Euros or dollars, the network is designed for a new cryptocurrency, also called Libra. This currency is backed by a reserve of nationally-issued currencies, and so Facebook hopes it will avoid the high volatility of cryptocurrencies like Bitcoin. As a result, Libra won’t be attractive to currency speculators, but Facebook hopes that it will, therefore, be useful for its stated goal – to be a “simple global currency and financial infrastructure that empowers billions of people.”

Reducing currency volatility is only one step towards meeting this goal of scaling cryptocurrencies to billions of users. The Libra blockchain design addresses how the network can maintain the high throughput and low transaction fees needed to compete with existing payment networks like Visa or MasterCard. However, a question that is equally important but as yet unanswered is how Facebook will develop a secure authentication and fraud prevention system that can scale to billions of users while maintaining good usability and low cost.

Facebook designed the Libra network, but in contrast to traditional payment networks, the Libra network is open. Anyone can send transactions through the network, and anyone can write programs (known as “smart contracts”) that control how, and under what conditions, funds can move between Libra accounts. To comply with anti-money-laundering regulations, Know Your Customer (KYC) checks will be performed, but only when Libra enters or leaves the network through exchanges. Transactions moving funds within the network should be accepted if they meet the criteria set out in the applicable smart contract, regardless of who sent them.

The Libra network isn’t even restricted to transactions transferring the Libra currency. Facebook has explicitly designed the Libra blockchain to make it easy for anyone to implement their own currency and benefit from the same technical facilities that Facebook designed for its currency. Other blockchains have tried this. For example, Ethereum has spawned hundreds of special-purpose currencies. But programming a smart contract to implement a new currency is difficult, and errors can be costly. The programming language for smart contracts within the Libra network is designed to help developers avoid some of the most common mistakes.

Facebook’s Libra and Securing the Calibra Wallet

There’s more to setting up an effective currency than just the technology: regulatory compliance, a network of exchanges, and monetary policy are essential. Facebook, through setting up the Libra Association, is focusing its efforts here solely on the Libra currency. The widespread expectation is, therefore, at least initially, the Libra cryptocurrency will be the dominant usage of the network, and most users will send and receive funds through the Calibra wallet smartphone app, developed by a Facebook subsidiary. From the perspective of the vast majority of the world, the Calibra wallet will be synonymous with Facebook’s Libra, and so damage to trust in Calibra will damage the reputation of Libra as a whole.

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The Government published its draft domestic abuse bill, but risks ignoring the growing threat of tech abuse

Dr Leonie Tanczer, who leads UCL’s “Gender and IoT” research team, reflects on the release of the draft Domestic Abuse Bill and points out that in its current form, it misses emphasis on emerging forms of technology-facilitated abuse.

On the 21st of January, the UK Government published its long-awaited Domestic Abuse Bill. The 196-page long document focuses on a wide range of issues from providing a first statutory definition of domestic abuse to the recognition of economic abuse as well as controlling and coercive non-physical behaviour. In recent years, abuse facilitated through information and communication technologies (ICT) has been growing. Efforts to mitigate these forms of abuse (e.g. social media abuse or cyberstalking) are already underway, but we expect new forms of “technology-facilitated abuse” (“tech abuse”) to become more commonplace amongst abusive perpetrators.

We are currently seeing an explosion in the number of Internet-connected devices on the market, from gadgets like Amazon’s Alexa and Google’s Home hub, to “smart” home heating, lighting, and security systems as well as wearable devices such as smartwatches. What these products have in common is their networked capability, and many also include features such as remote, video, and voice control as well as GPS location tracking. While these capabilities are intended to make modern life easier, they also create new means to facilitate psychological, physical, sexual, economic, and emotional abuse as well as controlling and manipulating behaviour.

Although so-called “Internet of Things” (IoT) usage is not yet widespread (there were 7.5 billion total connections worldwide in 2017), GSMA expects there to be 25 billion devices globally by 2025. Sadly, we have already started to see examples of these technologies being misused. An investigation last year by the New York Times showed how perpetrators of domestic abuse could use apps on their smartphones to remotely control household appliances like air conditioning or digital locks in order to monitor and frighten their victims. In 2018, we saw a husband convicted of stalking after spying on his estranged wife by hacking into their wall-mounted iPad.

The risk of being a victim of tech abuse falls predominantly on women and especially migrant women. This is a result of men still being primarily in charge of the purchase and maintenance of technical systems as well as women and girls being over-proportionally affected by domestic abuse.

The absence of ‘tech abuse’ in the draft bill

While the four objectives of the draft Bill (promote awareness, protect and support, transform the justice process, improve performance) are to be welcomed, the absence of sufficient reference to the growing rise of tech abuse is a significant omission and missed opportunity.

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