Dec 20th, 2010
Password Aging under Red Hat Enterprise Linux
Password Aging under Red Hat Enterprise Linux
Password aging is another technique used by system administrators to defend against bad passwords within an organization. Password aging means that after a specified period (usually 90 days), the user is prompted to create a new password. The theory behind this is that if a user is forced to change his password periodically, a cracked password is only useful to an intruder for a limited amount of time. The downside to password aging, however, is that users are more likely to write their passwords down.
There are two primary programs used to specify password aging under Red Hat Enterprise Linux: the chage command or the graphical User Manager (system-config-users) application. The -M option of the chage command specifies the maximum number of days the password is valid. For example, to set a user’s password to expire in 90 days, use the following command:
In the above command, replace with the name of the user. To disable password expiration, it is traditional to use a value of 99999 after the -M option (this equates to a little over 273 years). You can also use the chage command in interactive mode to modify multiple password aging and account details. Use the following command to enter interactive mode:
The following is a sample interactive session using this command:
