Rethinking Mandatory Password Changes

We are told to change our passwords every 90 days. The primary reason given to uses is that users pick bad passwords and they can only be trusted for less than 90 days before they could be hacked.  Many users will complain that it is difficult to select at least 4 complex passwords a year. If you pair that with the inability to reuse the last 6 passwords (minimum PCI DSS requirement), and the fact that users have more than one account that requires a password, you are looking at the requirement for potentially hundreds (current and recently used) of unique passwords that they may have to remember.

FTC Chief Technologist Lorrie Cranor wrote in March 2016 that it is time to reconsider mandatory password changes:

Unless there is reason to believe a password has been compromised or shared, requiring regular password changes may actually do more harm than good in some cases. (And even if a password has been compromised, changing the password may be ineffective, especially if other steps aren’t taken to correct security problems.)

Their research also showed that once a user password has been hacked, they were able to guess the next password the user would select with relative ease.

The Carleton researchers also point out that an attacker who already knows a user’s password is unlikely to be thwarted by a password change. As the UNC researchers demonstrated, once an attacker knows a password, they are often able to guess the user’s next password fairly easily. In addition, an attacker who has gained access to a user’s account once may be able to install a key logger or other malware that will allow them to continue to access the system, even if the user changes their password.

While there are environments that are less flexible because of compliance requirements, you should look at other solutions to the threat of hacking.

A change in the frequency and type of passwords you require addresses the issue from a users perspective, but doesn’t address the problem of the cyber-mess a user must face when an internet site it hacked and their very complex and long password may still be compromised.

Research suggests frequent mandatory expiration inconveniences and annoys users without as much security benefit as previously thought, and may even cause some users to behave less securely. Encouraging users to make the effort to create a strong password that they will be able to use for a long time may be a better approach for many organizations, especially when combined with slow hash functions, well-chosen salt, limiting login attempts, and password length and complexity requirements. And the best choice – particularly if your enterprise maintains sensitive data – may be to implement multi-factor authentication.

Maybe this holiday season is a good time to rethink your password procedures to see if there is anything you can do to make the situation better for your users.


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