May 2017 Archives

Find Security Champions in Blends of Organisational Culture

I was at the EuroUSEC ’17 workshop in Paris at the end of April. Our own Angela Sasse was also there to deliver the keynote talk, and Ruba Abu-Salma presented our paper “The Security Blanket of the Chat World: An Analytic Evaluation and a User Study of Telegram” (which was based on research by undergraduate students studying UCL’s COMP3096 “Research Group Project” module). I presented secondary analysis, conducted with Ingolf Becker and Angela Sasse, of a survey deployed at a large partner organisation. This analysis builds on research we presented at the Symposium on Usable Privacy and Security (SOUPS) in 2016. Based on survey responses and voluntary free-text comments, we saw potential for employees to inform policy from the ‘ground up’, in contradiction to the current trend for identifying security champions as local representatives of pre-determined policy.

Top-down security policies

Organisational policies are intended to promote a unified approach to security, one that all the organisation’s employees are expected to follow. If security procedures and mechanisms are unusable, policies risk being seen as impossible to follow, or may be sidelined if they lack clear relevance to business goals. This can result in deliberate or unwitting non-compliance, and workarounds to prescribed procedures.

Organisations may promote security champions, as local representatives to promote policy in their part of the organisation. However, these security champions can be effective only if policy is workable. Encouraging ‘top down’ policy compliance assumes that policy is correct, complete, and appropriate. It also assumes that policy applies to everyone equally and that employees have no role to play in shaping effective policy. Our analysis explores the potential for employees to inform effective policies, in particular whether it was possible to (i) identify local pockets of security expertise, and (ii) target engagement with employees that involves them in the creation of workable security solutions.

Identifying security champions ‘from the ground up’

Level	Attitude	Approach
1	Uninfluenced	Security behaviour is driven by personal knowledge.
2	Technically Controlled	Technical controls enforce compliance with policy.
3	Ad-hoc Knowledge and Application	Shallow understanding of policy. Knowledge absorbed from surrounding work environment.
4	Policy Compliant	Comprehensive knowledge and understanding of policy. Willing policy compliance. Role model for organisation’s security culture.
5	Active Approach to Security	Actively promote and advance security culture. Intent of policy carried into work activities Leverage well-understood values that support both security and business.

Employee security – Attitude-Levels. We studied an organisation with IT systems, so there were no participants at Level 1

A scenario-based survey was deployed in the partner company. Scenarios were based upon in-depth interviews with employees that explored security behaviours in the workplace. Each scenario involved a dilemma, where fixed options described different responses and included an element of non-compliance or an implicit cost. Participant choices indicate their Behaviour Type (above) and Attitude Level (below), which we recorded across groups of employees to characterise the security culture of the organisation and in four specific divisions. Both interviews and surveys represent a cross-section of divisions, locations, and age groups. We collected 608 survey responses; crucially, the survey allowed participants to comment on the scenarios and the available options – we also looked at 267 additional free-text comments that were provided.

Behaviour-Type	Description
Individualists	Rely on self for solutions
Egalitarians	Rely on social or group solutions
Hierarchists	Rely on existing systems or technologies
Fatalists	Take a ‘naive’ approach, that their actions are not significant in creating outcomes

Behaviour-Types

Continue reading Find Security Champions in Blends of Organisational Culture

Observing the WannaCry fallout: confusing advice and playing the blame game

As researchers who strive to develop effective measures that help individuals and organisations to stay secure, we have observed the public communications that followed the Wannacry ransomware attack of May 2017 with increasing concern. As in previous incidents, many descriptions of the attack are inaccurate – something colleagues have pointed out elsewhere. Our concern here is the advice being disseminated, and the fact that various stakeholders seem to be more concerned with blaming each other than with working together to prevent further attacks affecting organisations and individuals.

Countries initially affected in WannaCry ransomware attack (source Wikipedia, User:Roke)

Let’s start with the advice that is being handed out. Much of it is unhelpful at best, and downright wrong at worst – a repeat of what happened after Heartbleed, when people were advised to change their passwords before the affected organisations had patched their SSL code. Here is a sample of real advice sent out to staff in major organisation post-WannaCry:

“We urge you to be vigilant and not to open emails that are unexpected, unusual or suspicious in any way. If you experience any unusual computer behaviour, especially any warning messages, please contact your IT support immediately and do not use your computer further until advised to do so.”

Useful advice has to be correct and actionable. Users have to cope with dozens, maybe hundreds, of unexpected emails every day, most containing links and many accompanied by attachments, cannot take ten minutes to ponder each email before deciding whether to respond. Such instructions also implicitly and unfairly suggest that users’ ordinary behaviour plays a major role in causing major incidents like this one. RISCS advocates enlisting users as part of frontline defence. Well-targeted, automated blocking of malicious emails lessen the burden on individual users, and build resilience for the organisation in general.

In an example of how to confuse users, The Register reports that City of London Police sent out its “advice” via email in an attachment entitled “ransomware.pdf”. So users are simultaneously exhorted to be “vigilant” and not open emails and required to open an email in order to get that advice. The confusion resulting from contradictory advice is worse than the direct consequences of the attack: it enables future attacks. Why play Keystone Cyber Cops when UK National Technical Authority for such matters, the National Centre for Cyber Security, offers authoritative and well-presented advice on their website?

Our other concern is the unedifying squabbling between spokespeople for governments and suppliers blaming each other for running unsupported software, not paying for support, charging to support unsupported software, and so on, with and security experts weighing in on all sides. To a general public already alarmed by media headlines, finger-pointing creates little confidence that either party is competent or motivated to keep secure the technology on which our lives all now depend. When the supposed “good guys” expend their energy fighting each other, instead of working together to defeat the attackers, it’s hard to avoid the conclusion that we are most definitely doomed. As Columbia University professor Steve Bellovin writes, the question of who should pay to support old software requires broader collaborative thought; in avoiding that debate we are choosing to pay as a society for such security failures.

We would refer those looking for specific advice on dealing with ransomware to the NCSC guidance, which is offered in separate parts for SMEs and home users and enterprise administrators.

Much of NCSC’s advice is made up of things we all know: we should back up our data, patch our systems, and run anti-virus software. Part of RISCS’ remit is to understand why users often don’t follow this advice. Ensuring backups remain uninfected is, unfortunately, trickier than it should be. Ransomware will infect – that is, encrypt – not only the machine it’s installed on but any permanently-connected physical or network drive. This problem ought to be solved by cloud storage, but it can be difficult to find out whether cloud backups will be affected by ransomware, and technical support documentation often simply refers individuals to “your IT support”, even though vendors know few individuals have any. Dropbox is unusually helpful, and provides advice on how to recover from a ransomware attack and how far it can help. Users should be encouraged to read such advice in advance and factor it into backup plans.

There are many reasons why people do not update their software. They may, for example, have had bad experiences in the past that lead them to worry that security updates will fail or leave their system damaged, or incorporate unwanted changes in functionality. Software vendors can help here by rigorously testing updates and resisting the temptation to bundle in new features. IT support staff can help by doing their own tests that allow them to reassure their users that they will help resolve any resulting problems in a timely manner.

In some cases, there are no updates to install. The WannaCry ransomware attack highlighted the continuing use of desktop Windows XP, which Microsoft stopped supporting with security updates in 2014. A few organisations still pay for special support contracts, and Microsoft made an exception for WannaCry by releasing a security patch more widely. Organisations that still have XP-based systems should now investigate to understand why equipment using an unsafe, outdated operating system is still in use. Ideally, the software should be replaced with a more modern system; if that’s not possible the machine should be isolated from network connections. No amount of reminding users to patch their systems or telling them to “be vigilant” will be effective in such cases.

This article also appears on the Research Institute in Science of Cyber Security (RISCS) blog.

PayBreak able to defeat WannaCry/WannaCryptor ransomware

Recently I worked on some research with colleagues at Boston University (Manuel Egele, William Koch) and University College London (Gianluca Stringhini) into defeating ransomware. The fruit of our labor, PayBreak published this year in ACM ASIACCS, is a novel proactive system against ransomware. It happens to work against the new global ransomware threat, WannaCry. WannaCry is infecting more than 230,000 computers in 150 countries demanding ransom payments in exchange for access to precious files. This attack has been cited as being unprecidented, and the largest to date. Luckily, our research works against it.

PayBreak works by storing all the cryptographic material used during a ransomware attack. Modern ransomware uses what’s called a “hybrid cryptosystem”, meaning each ransomed file is encrypted using a different key, and each of those keys are then encrypted using another private key held by the ransomware authors. When ransomware attacks, PayBreak records the cryptographic keys used to encrypt each file, and securely stores them. When recovery is necessary, the victim retrieves the ransom keys, and iteratively decrypts each file.

Defeating WannaCry Ransomware

At this point, I think I’ve reverse engineered and researched something like 30 ransomware families, from over 1000 samples. Wannacry isn’t really much different than every other ransomware family. Those include other infamous families like Locky, CryptoWall, CryptoLocker, and TeslaLocker.

They all pretty much work the same way, including Wannacry. Actually, this comic sums up the ransom process the best I’ve seen. Every successful family today encrypts each file for ransom with a new unique “session” key, and encrypts each session key with a “private” ransom key. Those session keys are generated on the host machine. This is where PayBreak shims the generation, and usage of those keys, and saves them. Meaning, the encryption of those session keys by the ransomware’s private key is pointless, and defeated.

The PayBreak system doesn’t rely on any specific algorithm, or cryptographic library to be used by ransomware. Actually, Wannacry implemented, or atleast, statically compiled its own AES-128-CBC function. PayBreak can be configured to hook arbitrary functions, including that custom AES function, and record the parameters, such as the key, passed to it. However, a simpler approach in this case was to hook the Windows secure pseudorandom number generator function, CryptGenRandom, which the ransomware (and most others) use to create new session keys per file, and save the output of the function calls.

Recovering files is simply testing each of the recorded session keys with the encrypted files, until a successful decryption. Decrypting my file system of ~1000 files took 94 minutes.

Encrypted: Desert.jpg.WNCRY
Key used by Wannacry: cc24d9c8388fa566456ccec745e009c8
Decrypted: Desert.jpg

Thanks @jeffreycrowell for sharing a sample with me.
The full paper can be found here: https://eugenekolo.com/static/paybreak.pdf
SHA256 Hash of Sample: 24d004a104d4d54034dbcffc2a4b19a11f39008a575aa614ea04703480b1022c
WannaCry Custom AES: https://gist.github.com/eugenekolo/fe229be2a4230cf8322bf5537e291812

The original post appeared on Eugene Kolodenker’s blog.

The politics of the NHS WannaCrypt ransomware outbreak

You know you live in 2017 when the top headline on national newspapers relates to a ransomware attack on the National Heath Service, the UK Prime minister comments on the matter, and the the security researchers dealing with the outbreak are presented as heroic figures. As ever, The Register, has the most detailed and sophisticated technical article on the matter. But also strangely the most informative in terms of public policy. As if somehow, in our days, technical sophistication is a prerequisite also for sophisticated political comment on those matters. Other news outlets present a caricature, of the bad malware authors, the good security researcher and vendors working around the clock, the valiant government defenders, and a united humanity trying to beat the virus. I want to break that narrative open in this article, and discuss the actual political and social lessons we should be learning. In part to avoid similar disasters in the future.

First off, I am always surprised when such massive systemic outbreaks of malware, are blamed squarely on the author(s) of the malware itself, and the blame game ends there. It is without doubt that the malware author has a great share of responsibility. I personally think it is immoral to deploy ransomware in the wild, deny people access to their data, and seek to benefit from this. It is also a crime in the UK and elsewhere.

However, it is strange that a single author, or a small group of authors, without any major resources can have such a deep and widespread effect on major technological infrastructures. The absurdity becomes clear if we transpose the situation into the world of traditional engineering. Imagine all skyscrapers in major cities had to be evacuated, because a couple of teenagers with rocks were trying to blackmail business owners to pay up, to protect their precious glass windows. The fragility of software and IT systems seems to have no parallel in any other large scale engineering infrastructure — and this is not inherent, but the result of very specific micro-political, geo-political and economic decisions.

Lets take the WannaCrypt outbreak and look at the political and other social decisions that lead to the disaster — besides the agency of the malware authors:

The disaster was possible in part, and foremost, because IT systems within the UK critical NHS infrastructure are outdated — and for example rely on Windows XP that is not any more being maintained by Microsoft. Well, actually this is not strictly true: Microsoft does make security updates for Windows XP, but does not provide them for free — and instead Microsoft expects organizations that are locked in the OS to pay up to get patches and stay safe. So two key questions need to be asked …
Why is the NHS not upgrading to a new versions of Windows, or any other modern operating system? The answer is simple: line of business applications (LOB: from heath record management, specialist analysis and imaging software, to payroll) may not be compatible with new operating systems. On top of that a number of modern medical devices, such as large X-ray scanners or heart monitors, come with embedded computers running Windows XP — and only Windows XP. There is no way of upgrading them. The MEDJACK cyber-attacks were leveraging this to rampage through hospitals in 2015.
Is having LOB software tying you to an outdated OS, or medical devices costing millions that are not upgradeable, a fact of nature? No. It is down to a combination of terrible and naive procurement processes in health organizations, that do not take into account the need and costs if IT and security maintenance — and do not entrench it into the requirements and contracts for services, software and devices. It is also the result of the health software and devices industries being immature and unsophisticated as to the needs to secure IT. They reap the benefits of IT to make money, but without expending much of it to provide quality and security. The tragic state of security of medical devices has built the illustrious career of my friend Prof. Kevin Fu, who has found systemic attacks against implanted heart devices that could kill you, noob security bugs in medical device software, and has written extensively on the poor strategy to tackle these problem. So today’s attacks were a disaster waiting to happen — and expect more unless we learn the right lessons.
So given the terrible state of IT that prevents upgrading the OS, why is the NHS not paying up Microsoft to get security patches? That is because the government, and Jeremy Hunt in particular, back in 2014 decided to not pay up the money necessary to keep receiving security updates for Windows XP, despite being aware of the absolute reliance of the NHS on the outdated software. So in effect, a deliberate political decision was taken, at the highest level of the government to leave the NHS open to cyber attack. This is unlikely to be the last Windows XP security bug, so more are presumably to come.
Then there is the question of how malware authors, managed to get access to security bugs for windows XP? How did they get the tools necessary to attack such a mature, and rather common system, about 15 years after Windows XP was released, and only after it went out of maintenance? It turn out that the vulnerabilities they used, were in fact hoarded by the NSA as a cyber weapon — which was lost or stolen by hackers or leakers, and released into the wild! (The tool was codenamed EternalBlue). For may years, the computer security research community has been warning that stockpiling vulnerabilities in very common software for cyber-offense purposes, is dangerous. When those cyber weapons are lost, leaked, or even just used, there is proliferation of the technology necessary to attack, which criminals and foreign states can turn against critical infrastructure. This blog commented on the matter as recently as 8 March 2017 in a post entitled “What the CIA hack and leak teaches us about the bankruptcy of current “Cyber” doctrines”. This now feels like an unfortunately fulfilled prophesy, but the NHS attack was just the expected outcome of the US/UK and now common place doctrine around cyber — that contributes to, and leverages insecurity rather than security. Alternative public policy options exist of course.

So to summarize, besides the author of the malware, a number of other social and systemic factors contribute to making such cyber attacks possible: from poor security standards in heath informatics industries; poor procurement processes in heath organizations; lack of liability on any of the software vendors (incl. Microsoft) for providing insecure software or devices; cost-cutting from the government on NHS cyber security with no constructive alternatives to mitigate risks; and finally the UK/US cyber-offense doctrine that inevitably leads to proliferation of cyber-weapons and their use on civilian critical infrastructures.

It it those systemic factors that need to change to avoid future failures. Bad people wishing to make money from ransomware, or other badness, will always exist. There is a discipline devoted to preventing this, and it is called security engineering. It is time industry and goverment start taking its advice seriously.

This was originally posted on Conspicuous Chatter, the blog of Prof. George Danezis.

Underground abraCARDabra: Understanding carding forums

Paying for dinner? A taxi ride? A tropical drink? Sure. Swipe or tap your card and it is done. Convenient. Payment cards make it easy for us to make payments at “brick-and-mortar” locations and online marketplaces. However, they are also attractive targets for cybercriminals seeking to steal funds from the accounts linked to payment cards, as seen in this recent high-profile theft of credit cards affecting more than 1,000 hotels, for instance.

Theft of payment card information via phishing, skimming, or hacking, is usually the first step in the chain of payment card fraud. Other steps include sales, validation, and monetisation of the stolen data. These illicit deals are aided by underground online forums where cybercriminals actively trade stolen credit card information. To tackle payment card fraud, it is therefore important to understand the characteristics of these forums and the activity of miscreants using them. In our paper, presented at the 2017 APWG Symposium on Electronic Crime Research (eCrime2017), we analyse and discuss the characteristics of underground carding forums. We focus on the available products and prices, characteristics of sellers, and features of the forums. We won the Best Paper Award at eCrime2017.

Products

The main products available on carding forums are credit card numbers, dumps, and fullz. Credit card numbers comprise the information actually printed on credit cards, that is, cardholder name, card number (16 digits on most cards), expiry date, and the security code on the back of the card (usually 3 digits).

Dumps comprise stolen information from the tracks of magnetic stripe of a credit card. Dumps are usually obtained via skimmers. Skimmers are devices attached to Automated Teller Machines (ATMs) and Point of Sale (POS) terminals by miscreants to steal data from unsuspecting victims. Afterwards, the miscreants create clones of the skimmed credit cards and monetise the clones, for instance, by making illicit purchases with them.

Fullz contain further information about the cardholder. In other words, fullz usually comprise information printed on the card plus additional information such as bank account information, cardholder’s date of birth, Social Security number, etc.

Sellers

Generally, there are several types of participants on carding forums: sellers, buyers, intermediaries, mules, administrators, and others. These roles are not mutually exclusive; sellers may simultaneously be buyers. In this study, we focus on sellers since they come before buyers in the fraud chain.

Our approach

We studied previous work on underground marketplaces and forums, and derived the following hypotheses from the insights gained. We then searched for names of carding forums, found 25 names, and collected data from 5 active forums. We then tested the hypotheses on the data.

Hypothesis 1. Prices of fullz (credit card numbers and additional cardholder information) are higher than prices of credit card numbers.
Hypothesis 2. A small number of traders are responsible for a large
proportion of traffic.
Hypothesis 3. Most traders sell only one product type (that is, they are specialised).
Hypothesis 4. Specialised traders sell their products at lower prices than unspecialised traders.
Hypothesis 5. Carding forums have working reputation systems that are as sophisticated as those of legal marketplaces (for instance, eBay).
Hypothesis 6. The vast majority of actors do not operate on more than
one forum.

Summary of findings

Our analyses confirmed Hypothesis 1, Hypothesis 2, and Hypothesis 6. In other words, prices of fullz are indeed higher than prices of credit card numbers (credit card numbers: mean = $10.08, median = $10.00; fullz: mean = $31.82, median = $30.00). Also, a small number of traders are responsible for a large proportion of traffic. Finally, most sellers focus their efforts on a single forum, as expected.

Hypothesis 4 was partially rejected, while Hypothesis 3 and Hypothesis 5 were completely rejected. In other words, specialised sellers do not always sell their products at lower prices than the unspecialised ones, most sellers advertise more than one type of product, and most of the carding forums under study do not have working reputation systems that are as elaborate as those of legitimate online marketplaces.

In conclusion, dumps and fullz are relatively expensive; they are more than three times as expensive as credit card numbers. This may be due to the effort needed to obtain or monetise the data, the amount of available information, or differing supply and demand. Sellers have varying success. Even though some sellers complete hundreds of transactions, most sellers do not succeed in selling anything. This means that the trading sections of the forums are profitable distribution channels for high-profile actors. Finally, specialisation is not a key characteristic of sellers, not even of high-profile sellers.

Further details can be found in the full paper All Your Cards Are Belong To Us: Understanding Online Carding Forums, by Andreas Haslebacher, Jeremiah Onaolapo, and Gianluca Stringhini.

Online security won’t improve until companies stop passing the buck to the customer

It’s normally in the final seconds of a TV or radio interview that security experts get asked for advice for the general public – something simple, unambiguous, and universally applicable. It’s a fair question, and what the public want. But simple answers are usually wrong, and can do more harm than good.

For example, take the UK government’s Cyber Aware scheme to educate the public in cybersecurity. It recommends individuals choose long and complex passwords made out of three words. The problem with this advice is that the resulting passwords are hard to remember, especially as people have many passwords and use some infrequently. Consequently, they will be tempted to use the same password on multiple websites.

Password re-use is far more of a security problem than insufficiently complex passwords, so advice that doesn’t help people manage multiple passwords does more harm than good. Instead, I would recommend remembering your most important passwords (like banking and email), and store the rest in a password manager. This approach isn’t perfect or suitable for everyone, but for most people, it will improve their security.

Advice unfit for the real world

Cyber Aware also tells people not to write down their passwords, or let anyone else know them – banks require the same thing. But we know that people commonly share their banking credentials with family, for legitimate reasons. People also realise that writing down passwords is a pretty good approach if you’re only worried about internet hackers, rather than people who can get close to you to see the written notes. Security advice that doesn’t stand up to scrutiny or doesn’t fit with people’s lives will be ignored – and will discredit the organisation offering it.

Because everyone’s situation is different, good security advice should include helping people to understand what risks they should be worried about, and to take steps that mitigate these risks. This advice doesn’t have to be complicated. Teen Vogue published a tutorial on how to select and configure a secure messaging tool, which very sensibly explains that if you are more worried about invasions of privacy from people who can get their hands on your phone, you should make different choices than if you are just concerned about, for example, companies spying on you.

The Teen Vogue article was widely praised by security experts, in stark contrast to an article in The Guardian that made the eye-catching claim that encrypted messaging service WhatsApp is insecure, without making clear that this only applies in an obscure and extremely unlikely set of circumstances.

Zeynep Tufekci, a researcher studying the effects of technology on society, reported that the article was exploited to legitimise misleading advice given by the Turkish government that WhatsApp is unsafe, resulting in human rights activists using SMS instead – which is far easier for the government to censor and monitor.

The Turkish government’s “security advice” to move from WhatsApp to less secure SMS was clearly aimed more at assisting its surveillance efforts than helping the activists to whom the advice was directed. Another case where the advice is more for the benefit of the organisation giving it is that of banks, where the terms and conditions small print gives incomprehensible security advice that isn’t true security advice, instead merely a legal technique to allow the banks wiggle room to refuse to refund victims of fraud.

Continue reading Online security won’t improve until companies stop passing the buck to the customer