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Spafford On Security Myths and Passwords
An anonymous reader writes "In a recent blog post, Eugene Spafford examines password security along with related issues and myths. In particular, he discusses how policies that may not necessarily make much sense anymore end up being labeled 'best practices,' and then propagated based on their reputation as such."
I worked at a company that rolled out increasingly stringent password policies. It got to a point where the passwords required upper and lower case characters, numbers, non-alpha numeric characters, and (this is the kicker) were required to be changed every few weeks.
I asked around, and gradually discovered that most of the people I worked with had ended up (after months of dilligently trying to adhere to this policy properly) had begun writing their passwords down at their desks.
Writing. Their. Passwords. Down.
It's like this well intentioned security policy had short-circuited itself and put the company in a position far worse than it had been before the reforms. None of the people involved were bad, in fact, I worked with a fine bunch of people who really cared about security and individually had great ideas for making the company safer, but when they were all implemented simultaneously: Ka-BLAM.
A security policy cannot be a list of best practices, it has to be a designed holistic plan that takes into consideration the very human nature of the people it is protecting.
I would expect that if passwords are required to be changed on a regular basis, then that would be more reason to write them down (if they're secure they're probably harder to remember). In this case it would seem that less-regular changing would be beneficial, resulting in less passwords being scribbled on pieces of paper and left around on the desk, or in the bin.
Yeah, but when is the last time you saw ANY software that actually echoed passwords to the screen? Basic security says that this should never occur. Unless you're really good at reading keystrokes, that isn't a real concern.
The problem lies with badly designed operating system/windowing system software that allow windows to grab focus. No window should be allowed to programmatically, without user intervention, pop to the foreground and get focus (whether it's a pop-up ad or any sort of dialogue). Unfortunately, this happens all the time. Especially windows applications love to pop up messages, dialogues, windows, and all allow you to quickly (without noticing) press OK and continue typing your password in plain sight in the application that just hijacked your focus! XP's "prevent applications from stealing focus" doesn't always work, and never works if an application happens to be spawning in the background (like during startup, which might be a good time to enter a password into putty's pagent for example).. *sigh*
SCO employee? Check out the bounty
I agree with the article, and not the parent post. Constant changing of a frequently used password is a complete failure in the exploration of logic regarding passwords. It is laziness, plain and simple; the reliance on the folklore of old to tell us what we should do. Frequent Password Changing Makes a System More Secure is an old wives tale.
Over time, even a hard password will be memorized by your average user. This password does not somehow become more insecure over time, because, as the article points out, the largest vulnerabilities are not due to the cracking of passwords, but rather human error, ignorance, and/or incompetance. These should decrease with time. The user should become better educated and better able to remember the password, thus less likely to give it out. Only the chance of human error increases slightly (typing password in login box and such). Of the three, this presents the least risk by far of those three, and generally the user is aware of this occurrance and with proper education will know to immediately change their password.
Forcing a user to change password frequently is likely to only cause them to alter one character (likely the last) in the password because committing another secure password to memory is difficult. This causes both usability and security to be comprimised in the same fell swoop. The other option is that they will write the password down or otherwise record it, thus defeating its security. If you've got users with photographic memories who instantly memorize a new hard password every month, you must be the luckiest damn admin in the world.
As the article points out, modern computing and cracking techniques expose vulnerabilities much more quickly, so passwords would have to be changed so frequently as to make a changing password policy useless in many environments anyway.
Caveat:
The opposite is true of Administrator passwords or others which are rarely used. These are generally not committed to memory, and likely documented in some fashion (hopefully they are, or when the admin leaves you're screwed). If they're meant to protect a truly important system, a biometric and/or time sensitive method (such as a synchronized continously changing key generator) should be used in addition to the password. Changing these passwords with some frequency is a good idea, as it forces someone to ensure the validity of the current password (the account is not locked or disabled) as well as provide the aforementioned small measure of protection against cracking.
Please, stop forcing password changes on user accounts. Its a stupid idea. It serves no purpose other than to ensure the latest user password is written down at every desk.
Rant complete.
// harborpirate
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