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.