March 4, 2012 Leave a comment
In recent months the “dead horse” of password-based authentication got some new life in the form of so-called ‘password haystacks‘. An approach introduced by well-known security expert (and one of my favorite gurus) Steve Gibson relies on the knowledge of the logic used by password brute force attackers. In essence the attackers – after trying a list of well-known passwords (“password”, “123456”, “cat” etc.), their variations (“pa$$w0rd”) and finally plain dictionary – switch to ‘pure guessing’ when arbitrary combination of alphanumeric characters and some special signs is generated and tried methodically until the password is guessed. Hence the “brute force” nature of the attack. So far the best prescription for passwords was to make them both random and very long – an advise routinely ignored by the users community as it made such passwords extremely hard for humans to remember. What Steve came out with is that passwords with similarly high “strength” (i.e. resistance to guessing) could be created by artificially increasing their length (each added character increases time needed to crack it exponentially) and the space of characters used in them (the bigger variety of small, capital case, number and special characters is used the more combinations are possible – again drastically increasing the cracking time) by, say, prepending or appending some easy-to-remember “padding” to passwords. For example, ‘000Johny000’ is infinitely harder to brute force than ‘johny’ – yet it requires comparable effort for humans to remember them. Makes perfect sense – you come out with your own secret “padding” pattern, and use it to enhance your simple but consequently easy-to-guess passwords. Once enhanced such passwords are both easy to remember and hard to crack (get more detailed explanation from the source here). Sounds like a perfect solution, huh?
Up to the point. While the “haystack” approach certainly adds to the password-based security – it is hardly the end of the game. Like anything else in security, password attacks are never ending cat-and-mouse game between the ‘locks’ and the ‘keys’. Thus it’s a matter of time till fraudsters update their password guessing algorithms/tools to check ‘popular padding’ patterns first before switching to ‘pure brute forcing’. Not to mention the possibility of ‘leaking’ your password in some other way (e.g. through phishing site) thus revealing the “secret sauce” of all your strong passwords – the “padding pattern” – to the attackers.
At the end of the day, as often mentioned in the past, passwords as viable protection mechanism are pretty much dead (mostly). Indeed, other approaches like multi-factor authentication have no real alternatives no matter what clever way we come out to make our passwords less guessable.