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GCHQ wants to set your passwords. In a good way

Enough already with the strength meters and frequent changes says security agency

By Darren Pauli, 11 Sep 2015

Britain's spy agency the GCHQ has changed its password security guidance in a new document offering sensible advice that, if followed, should harden systems and make life easier for admins and users.

The guidance advocates a ban on password strength meters, mandatory resets, and predictable combinations, instead encouraging brute force rate limiting and reduced access controls.

The advice is not for the likes of GCHQ itself who should maintain their own air-gapped faraday cages security systems according to risk appetite.

The guide covers the obvious such as how passwords can be cracked and the need to change from pre-installed defaults, but also offers solid advice that admins should only dole out passwords where they are required and allowing the use of password storage lockers.

GCHQ security director general Ciaran Martin outlines the password thought leadership in a report (PDF).

"Every single user in the UK public sector has at least one, and most likely considerably more, work-related passwords," Martin says.

"By simplifying your organisation's approach, you can reduce the workload on users, lessen the support burden on IT departments, and combat the false sense of security that unnecessarily complex passwords can encourage."

The report busts old and damaging myths too; kill the horrible mandatory password reset and instead force changes only in the event of a possible security breach.

Much of the advice is found in research covered by Microsoft here and here, and by Google here.

It does not cover some of Redmond's controversial advice that passwords should be reused across non-sensitive don't-care-if-it's-hacked sites.

However GCHQ agrees that passwords should not be subject to regular changes. This is because users who start off with a strong password will end up with a simple one due to the frustration of trying to remember it.

It also says password strength meters ought to be consigned to the bin, replaced with a blacklist of predictable passwords and some brute force throttling limited to 10 guesses.

Password managers are helpful but are a risk, the document says, since the security of a password is tied to its container and encryption used.

The document continues; do not share passwords, ever. It is such a crime that it should not even be broken in the event of an "emergency" requiring access to medical records, and instead an RFID tag or a token should be used to obtain temporary access.

The G Men subscribe to the church of XKCD, advocating the use of that comic's sometimes divisive Horse Battery Staple format of random yet easy to remember passwords over those requiring a mix of upper and lower case letters, and numbers.

Admins should offer users a scheme that offers memorable combination possibilities. Those would include words of the Consonant Consonant Vowel Consonant construction.

Access rights are critical. Admin accounts are not a plaything used for Youtube, but something to be used sparingly. System admins and other remote users must be burdened with high levels of security, including unique logins, two factor authentication, and "absolutely no default passwords".

Cleartext passwords are heresy. Such things must be regularly sought out and crushed, replaced with salted hashing. The preferred cryptographic function here is SHA 256 and PBKDF2.

Outsourcers must sign a contract to promise they will protect passwords and adhere to the policies, the document concludes. ®

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