Should you phish your own employees?

No. Please don’t. It does little for security but harms productivity (because staff spend ages pondering emails, and not answering legitimate ones), upsets staff and destroys trust within an organisation.

Why is phishing a problem?

Phishing is one of the more common ways by which criminals gain access to companies’ passwords and other security credentials. The criminal sends a fake email to trick employees into opening a malware-containing attachment, clicking on a link to a malicious website that solicits passwords, or carrying out a dangerous action like transferring funds to the wrong person. If the attack is successful, criminals could impersonate staff, gain access to confidential information, steal money, or disrupt systems. It’s therefore understandable that companies want to block phishing attacks.

Perimeter protection, such as blocking suspicious emails, can never be 100% accurate. Therefore companies often tell employees not to click on links or open attachments in suspicious emails.

The problem with this advice is that it conflicts with how technology works and employees getting their job done. Links are meant to be clicked on, attachments are meant to be opened. For many employees their job consists almost entirely of opening attachments from strangers, and clicking on links in emails. Even a moderately well targeted phishing email will almost certainly succeed in getting some employees to click on it.

Companies try to deal with this problem through more aggressive training, particularly sending out mock phishing emails that exhibit some of the characteristics of phishing emails but actually come from the IT staff at the company. The company then records which employees click on the link in the email, open the attachment, or provide passwords to a fake website, as appropriate.

The problem is that mock-phishing causes more harm than good.

What harm does mock-phishing cause?

I hope no company would publicly name and shame employees that open mock-phishing emails, but effectively telling your staff that they failed a test and need remedial training will make them feel ashamed despite best intentions. If, as often recommended, employees who repeatedly open mock-phishing emails will even be subject to disciplinary procedures, not only will mock phishing lead to stress and consequent loss of productivity, but it will make it less likely that employees will report when they have clicked on a real phishing email.

Alienating your employees in this way is really the last thing a company should do if it wants to be secure – something Adams & Sasse pointed out as early as 1999. It is extremely important that companies learn when a phishing email has been opened, because there is a lot that can be done to prevent or limit harm. Contrary to popular belief, attacks don’t generally happen “at the speed of light” (it took three weeks for the Target hackers to steal data, from the point of the initial breach). Promptly cleaning potentially infected computers, revoking compromised credentials, and analysing network logs, is extremely effective, but works only if employees feel that they are on the same side as IT staff.

More generally, mock-phishing conflicts with and harms the trust relationship between the company and employees (because the company is continually probing them for weakness) and between employees (because mock-phishing normally impersonates fellow employees). Kirlappos and Sasse showed that trust is essential for maintaining employee satisfaction and for creating organisational resilience, including ability to comply with security policies. If unchecked, prolonged resentment within organisation achieves exactly the opposite – it increases the risk of insider attacks, which in the vast majority of cases start with disgruntlement.

There are however ways to achieve the same goals as mock phishing without the resulting harm.

Measuring resilience against phishing

Companies are right to want to understand how vulnerable they are to attack, and mock-phishing seems to offer this. One problem however is that the likelihood of opening a phishing email depends mainly on how well it is written, and so mock-phishing campaigns tell you more about the campaign than the organisation.

Instead, because every organisation inevitably receives many phishing emails, companies don’t need to send out their own. Use “genuine” phishing emails to collect the data needed, but be careful not to deter reporting. Realistically, however, phishing emails are going to be opened regardless of what steps are taken (short of cutting off Internet email completely). So organisations’ security strategy should accommodate this.

Reducing vulnerability to phishing

Following mock-phishing with training seems like the perfect time to get employees’ attention, but is this actually an ineffective way to reduce an organisations’ vulnerability to phishing. Caputo et. al tried this out and found that training had no significant effect, regardless of how it was phrased (using the latest nudging techniques from behavioural economists, an idea many security practitioners find very attractive). In this study, the organisation’s help desk staff was overwhelmed by calls from panicked employees – and when told it was a “training exercise”, many expressed frustration and resentment towards the security staff that had tricked them. Even if phishing prevention training could be made to work, because the activity of opening a malicious email is so close to what people do as part of their job, it would disrupt business by causing employees to delete legitimate email or spend too long deciding whether to open them.

A strong, unambiguous, and reliable cue that distinguishes phishing emails from legitimate ones would help, but until we have secure end-to-end encrypted and authenticated email, this isn’t possible. We are left with the task of designing security systems accepting that some phishing emails will be opened, rather than pretending they won’t be and blaming breaches on employees that fail to meet an unachievable bar. If employees are consistently being told that their behaviour is not good enough but not being given realistic and actionable advice on how to do better, it creates learned helplessness, with all the negative psychological consequences.

Comply with industry “best-practice”

Something must be done to protect the company; mock-phishing is something, therefore must must be done. This perverse logic is the root cause of much poor security, where organisations think they must comply with so-called “best practice” – seldom more than out-of-date folk tradition – or face penalties when there is a breach. It’s for this reason that bad security guidance persists long after it has been shown to be ineffective, such as password complexity rules.

Compliance culture, where rules are blindly followed without there being evidence of effectiveness, is one of the worst reasons to adopt a security practice. We need more research on how to develop technology that is secure and that supports an organisation’s overall goals. We know that mock-phishing is not effective, but what’s the right combination of security advice and technology that will give adequate protection, and how do we adapt these to the unique situation of each company?

What to do instead?

The security industry should take the lead of the aerospace industry and recognise the “blame and train” isn’t an effective or acceptable strategy. The attraction of mock phishing exercises to security staff is that they can say they are “doing something”, and like the idea of being able to measure behaviour change as a result of it – even though research points the other way. If vendors claim they have examples of mock phishing training reducing clicks on links, it is usually because employees have been trained to recognise only the vendor’s mock phishing emails or are frightened into not clicking on any links – and nobody measures the losses that occur because emails from actual or potential customers or suppliers are not answered. “If security doesn’t work for people, it doesn’t work.

When the CIO of a merchant bank found that mock phishing caused much anger and resentment from highly paid traders, but no reduction in clicking on links, he started to listen to what it looked like from their side. “Your security specialists can’t tell if it is a phishing email or not – why are you expecting me to be able to do that?” After seeing the problem from their perspective, he added a button to the corporate mail client labeled “I’m not sure” instead, and asked staff to use the button to forward emails they were not sure about to the security department. The security department then let the employee know, plus list all identified malicious emails on a web site employees could check before forwarding emails. Clicking on phishing links dropped to virtually zero – plus staff started talking to each other about phishing emails they had seen, and what the attacker was trying to do.

Security should deal with the problems that actually face the company; preventing phishing wouldn’t have stopped recent ransomware attacks. Assuming phishing is a concern then, where possible to do so with adequate accuracy, phishing emails should be blocked. Some will get through, but with well engineered and promptly patched systems, harm can be limited. Phishing-resistant authentication credentials, such as FIDO U2F, means that stolen passwords are worthless. Common processes should be designed so that the easy option is the secure one, giving people time to think carefully about whether a request for an exception is legitimate. Finally, if malware does get onto company computers, compartmentalisation will limit damage, effective monitoring facilitates detection, and good backups allow rapid recovery.

 

An earlier version of this article was previously published by the New Statesman.

The end of the billion-user Password:Impossible

XKCD: “Password Strength”

This week, the Wall Street Journal published an article by Robert McMillan containing an apology from Bill Burr, a man whose name is unknown to most but whose work has caused daily frustration and wasted time for probably hundreds of millions of people for nearly 15 years. Burr is the author of the 2003 Special Publication 800-63. Appendix A from the US National Institute of Standards and Technology: eight pages that advised security administrators to require complex passwords including special characters, capital letters, and numbers, and dictate that they should be frequently changed.

“Much of what I did I now regret,” Burr told the Journal. In June, when NIST issued a completely rewritten document, it largely followed the same lines as the NCSCs password guidance, published in 2015 and based on prior research and collaboration with the UK Research Institute in Science of Cyber Security (RISCS), led from UCL by Professor Angela Sasse. Yet even in 2003 there was evidence that Burr’s approach was the wrong one: in 1999, Sasse did the first work pointing out the user-unfriendliness of standard password policies in the paper Users Are Not the Enemy, written with Anne Adams.

How much did that error cost in lost productivity and user frustration? Why did it take the security industry and research community 15 years to listen to users and admit that the password policies they were pushing were not only wrong but actively harmful, inflicting pain on millions of users and costing organisations huge sums in lost productivity and administration? How many other badly designed security measures are still out there, the cyber equivalent of traffic congestion and causing the same scale of damage?

For decades, every password breach has led to the same response, which Einstein would readily have recognised as insanity: ridiculing users for using weak passwords, creating policies that were even more difficult to follow, and calling users “stupid” for devising coping strategies to manage the burden. As Sasse, Brostoff, and Weirich wrote in 2001 in their paper Transforming the ‘Weakest Link’, “…simply blaming users will not lead to more effective security systems”. In his 2009 paper So Long, and No Thanks for the Externalities, Cormac Herley (Microsoft Research) pointed out that it’s often quite rational for users to reject security advice that ignores the indirect costs of the effort required to implement it: “It makes little sense to burden all users with a daily task to spare 0.01% of them a modest annual pain,” he wrote.

When GCHQ introduced the new password guidance, NCSC head Ciaran Martin noted the cognitive impossibility of following older policies, which he compared to trying to memorise a new 600-digit number every month. Part of the basis for Martin’s comments is found in more of Herley’s research. In Password Portfolios and the Finite-Effort User, Herley, Dinei Florencio, and Paul C. van Oorschot found that the cognitive load of managing 100 passwords while following the standard advice to use a unique random string for every password is equivalent to memorising 1,361 places of pi or the ordering of 17 packs of cards – a cognitive impossibility. “No one does this”, Herley said in presenting his research at a RISCS meeting in 2014.

The first of the three questions we started with may be the easiest to answer. Sasse’s research has found that in numerous organisations each staff member may spend as much as 30 minutes a day on entering, creating, and recovering passwords, all of it lost productivity. The US company Imprivata claims its system can save clinicians up to 45 minutes per day just in authentication; in that use case, the wasted time represents not just lost profit but potentially lost lives.

Add the cost of disruption. In a 2014 NIST diary study, Sasse, with Michelle Steves, Dana Chisnell, Kat Krol, Mary Theofanos, and Hannah Wald, found that up to 40% of the time leading up to the “friction point” – that is, the interruption for authentication – is spent redoing the primary task before users can find their place and resume work. The study’s participants recorded on average 23 authentication events over the 24-hour period covered by the study, and in interviews they indicated their frustration with the number, frequency, and cognitive load of these tasks, which the study’s authors dubbed “authentication fatigue”. Dana Chisnell has summarised this study in a video clip.

The NIST study identified a more subtle, hidden opportunity cost of this disruption: staff reorganise their primary tasks to minimise exposure to authentication, typically by batching the tasks that require it. This is a similar strategy to deciding to confine dealing with phone calls to certain times of day, and it has similar consequences. While it optimises that particular staff member’s time, it delays any dependent business process that is designed in the expectation of a continuous flow from primary tasks. Batching delays result not only in extra costs, but may lose customers, since slow responses may cause them to go elsewhere. In addition, staff reported not pursuing ideas for improvement or innovation because they couldn’t face the necessary discussions with security staff.

Unworkable security induces staff to circumvent it and make errors – which in turn lead to breaches, which have their own financial and reputational costs. Less obvious is the cost of lost staff goodwill for organisations that rely on free overtime – such as US government departments and agencies. The NIST study showed that this goodwill is dropping: staff log in less frequently from home, and some had even returned their agency-approved laptops and were refusing to log in from home or while travelling.

It could all have been so different as the web grew up over the last 20 years or so, because the problems and costs of password policies are not new or newly discovered. Sasse’s original 1999 research study was not requested by security administrators but by BT’s accountants, who balked when the help desk costs of password problems were tripling every year with no end in sight. Yet security people have continued to insist that users must adapt to their requirements instead of the other way around, even when the basis for their ideas is shown to be long out of date. For example, in a 2006 blog posting Purdue University professor Gene Spafford explained that the “best practice” (which he calls “infosec folk wisdom”) of regular password changes came from non-networked military mainframes in the 1970s – a far cry from today’s conditions.

Herley lists numerous other security technologies that are as much of a plague as old-style password practices: certificate error warnings, all of which are false positives; security warnings generally; and ambiguous and non-actionable advice, such as advising users not to click on “suspicious” links or attachments or “never” reusing passwords across accounts.

All of these are either not actionable, or just too difficult to put into practice, and the struggle to eliminate them has yet to bear fruit. Must this same story continue for another 20 years?

 

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

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.

Biometrics for payments

HSBC and First Direct recently announced that they are introducing fingerprint and voice recognition authentication for customers of online and telephone banking. In my own research, I first found nearly 20 years ago that people who have a multitude of passwords and PINs cannot manage them as security experts want them to. As the number of digital devices and services we use has increased rapidly, managing dozens of login details has become a headache for most people. We recently reported that most bank customers juggle multiple PINs, and are unable to follow the rules that banks set in their contracts. Our research also found that many people dislike the 2-factor token solutions that are currently used by many UK banks.

Passwords as most people use them today are not particularly secure. Attackers can easily attempt to collect information on individuals, using leaks of password files not properly protected by some websites, “phishing” scams or malware planted on people’s computers. Reusing a banking password on other websites – something that many of us do because we cannot remember dozens of different passwords – is also a significant security risk.

The introduction of fingerprint recognition on smartphones – such as the iPhone – has delighted many users fed up with entering their PINs dozens of times a day. So the announcement that HSBC and other banks will be able to use the fingerprint sensor on their smartphones for banking means that millions of consumers will finally be able to end their battle with passwords and PINs and use biometrics instead. Other services people access from their smartphones are likely to follow suit. And given the negative impact that cumbersome authentication via passwords and PINs has on staff productivity and morale in many organisations, we can expect to see biometrics deployed in work contexts, too.

But while biometrics – unlike passwords – do not require mental gymnastics from users, there are different usability challenges. Leveraging the biometric from the modality of interaction – e.g. voice recognition phone-based interactions – makes authentication an easy task, but it will work considerably better in quiet environments than noisy ones – such as a train stations or with many people talking in the background. As many smartphone users have learnt, fingerprint sensors have a hard time recognising cold and wet fingers. And – as we report in a paper presented at IEEE Identity, Security and Behavior Analysis last week – privacy concerns mean some users ‘don’t like putting their face on the Internet’. Biometrics can’t come soon enough for most users, but there is still a lot of design and testing work to be done to make biometrics work for different interaction, physical and social contexts.

A Digital Magna Carta?

I attended two privacy events over the past couple of weeks. The first was at the Royal Society, chaired by Prof Jon Crowcroft.

All panelists talked about why privacy is necessary in a free, democratic society, but also noted that individuals are ill equipped to achieve this given the increasing number of technologies collecting data about us, and the commercial and government interests in using those.

During the question & answer session, one audience member asked if we needed a Digital Charter to protect rights to privacy. I agreed, but pointed out that citizens and consumers would need to express this desire more clearly, and be prepared to take collective action to stop the gradual encroachment.

The second panel – In the Digital Era – Do We Still Have Privacy? – organised in London by Lancaster University this week as part of its 50th Anniversary celebrations, chaired by Sir Edmund Burton.

One of the panelists – Dr Mike Short from Telefonica O2 – stated that it does not make commercial sense for a company to use data in a way that goes against their customer’s privacy preferences.

But there are service providers that force users to allow data collection – you cannot have the service unless you agree to your data being collected (which goes against the OECD principles for informed consent) or the terms & conditions so long that users don’t want to read them – and even if they were prepared to read them, they would not understand them without a legal interpreter.

We have found in our research at UCL (e.g. Would You Sell Your Mother’s Data, Fairly Truthful) that consumers have a keen sense of ‘fairness’ about how their data is used – and they definitely do not think it ‘fair’ for them to be used against their express preferences and life choices.

In the Q & A after the panel the question of what can be done to ensure fair treatment for consumers, and the idea of a Digital Charter, was raised again. The evening’s venue was a CD’s throw away from the British Library, where the Magna Carta is exhibited to celebrate its 800th anniversary. The panelists reminded us that last year, Sir Tim Berners-Lee called for a ‘Digital Magna Carta’ – I think this is the perfect time for citizens and consumers to back him up, and unite behind his idea.

Is sending shoppers ads by Bluetooth just a bit creepy?

Using Bluetooth wireless networking to send information to nearby smartphones, beacon technology could transform how retailers engage with their customers. But customers will notice how their information is used to personalise these unsolicited adverts, and companies that fail to respect their privacy may get burned.

UK retailer House of Fraser is to introduce beacon-equipped mannequins to its Aberdeen store, which will deliver details about the clothes and accessories the mannequin is wearing to the smartphones of customers within 50 metres. In London’s Regent Street, around 100 stores have installed Apple’s iBeacons, able to send adverts to smartphones to entice passers-by to come inside.

A sort of precursor to the “internet of things”, beacon technology has great potential to enhance consumer experience: providing access to relevant information more quickly, or offering rewards and discounts for loyal shoppers. Some retailers may rearrange their store based on analysing data from customers’ shopping habits. It has uses outside of marketing too, such as providing contactless payments, tourist information at museums, or gate information at airports.

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