Why you can do so much better than the three-random-word rule that’s still being churned out by the NCSC
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I’m about to so do something I’m sure won’t shock regular readers: pick an argument with the powers that be. The organisation in question, being the National Cyber Security Centre (NCSC) which, by and large, does a splendid job in both public and private sectors in matters of security advice and support. By and large, but not on one occasion recently when it decided the time was right to remind us of some password construction advice it first offered five years ago. It was wrong then and remains so to this day.
Using the perfectly reasonable hashtag of #thinkrandom, that advice was to use three random words as your password. That’s three words, not four, so you can forget about the XKCD comic suggestion of “correct, horse, battery, staple” that’s wedged itself into cyber security folklore. Not that you should use it anyway, as password reuse is obviously verboten if you want to maintain any semblance of a strong security posture.
While admitting the use of three random words is “not a password panacea”, the latest NCSC posting serves to press home the message that it’s better than using traditional password complexity advice, because the latter relies upon us memorising lots of long and complex strings. Using three random words, we are advised, creates passwords that are “strong enough for many purposes”, and helps get around the reuse problem that it says traditional complex passwords creates.
Random access memories
Let’s deal with the last of these first: password reuse. There is absolutely no bloody difference between trying to remember 97 unique complex and random password strings and doing so with 97 three random word passphrases. You will fail unless you are a memory savant. That is a fact. It’s a fact because as humans we are simply not wired to remember random things.
This brings me to the second problem I have with the advice: the reality of randomness. Most people, most of the time, will choose three words that are far from random when constructing a whole bunch of passphrases. What people will do is, totally subconsciously, adopt patterns in the phrases they come up with. Patterns in both the connections between the words used to make recall easier and patterns between the passphrases themselves to make multiple ones easier to recall.
Humans just don’t do randomness well; that’s why there are computer-me-bobs for creating truly random stuff, and more on that later. There’s a really interesting piece of research from the University of Cambridge Computer Laboratory, admittedly now almost a decade old but still relevant, that explains this very well. Its evidence on multi-word passphrases was pretty damning: “By our metrics, even five-word phrases would be highly insecure against offline attacks,” the researchers found, because people naturally sway towards speech rather than randomness. “Phrases like young man which come up often in speech are proportionately more likely to be chosen than rare phrases like young table” the research concluded. Which is exactly what I would expect.
There’s an app for that
Look, I perfectly understand plenty of security professionals disagree with me here. Their argument generally being along the same lines as the NCSC, that adopting a three random words approach will create stronger passwords than those we often see being used and reused today. This is true, and I’m not suggesting that Password, or P@ssw0rd, or even P@ssw0rd1 is a super-duper credential to be using. What I am suggesting is that, rather than getting people to use three supposedly random words, it would be far better to advise them to use some form of secure password manager instead.
Skip the whole three words thing, don’t mention it at all, go straight for the “use a password manager dammit” jugular. That way you can create truly random and complex and extremely long passwords, or the application can, and have a unique one for every login.
Of course, the perennial problem of master password creation rears its very ugly head once more. Rather than go over old ground involving muscle memory, encrypted USB sticks (which need yet another password) or a biometric device (JEMpass) and even dice with multiple patterns rolled randomly into a locked box (DiceKeys), let’s approach this from the three random words angle. Or, rather, let’s not. Just three words, no matter how random, would make a spectacularly poor master password if you ask me. Instead, go for five or six, or more if your memory will allow.
These would, of course, need to be random rather than your idea of random. Which is where one password manager, in fact 1Password, comes in. Did you see what I did there? Anyway, it has a password generator that anyone can use – which has the option of generating a passphrase using random words. Just select the “memorable password” dropdown, set the number of words to something you are comfortable with, and you’re away. Other services, of course, are also available, such as Kaspersky's own password generator.
As I say, don’t go for anything too short as this is the key that unlocks all your other passwords. I’d also avoid unchecking the “full words” box as this produces gibberish words that aren’t really easier than a long password to memorise. Practise typing the result over and over to get that muscle memory working, and if you are a 1Password user, be sure to save the “emergency kit” that can be printed out and stored somewhere secure. The reality is that for 99% of use cases a threat actor isn’t going to ransack your house searching for a master password, nor your office for that matter. If you do fall into the 1% then the chances are high that you’ll already be using some kind of security protocol that makes the entire three random words argument moot anyway.
Talking of passwords in the workplace, I can’t wrap up this conversation without mentioning some more research, this time from Beyond Identity. This found that not only did nearly a quarter of employees questioned still have access to accounts from a previous job, but 41% admitted to sharing passwords in the office, and 20% used the same passwords at home as they did for work-related accounts. Just in case you wondered why I bang on about the importance of password hygiene, month after month.
Keyword: Skip the three words thing, go straight for the ‘use a password manager, dammit’ jugular