I just installed Ubuntuy 18.10 on one of my computers, and am trying to understand why a series of passwords are not working, even though they are completely random character strings.
I started by trying to change the initial password to the following character string: XB76cD_*P789_;Eqy10
I receive the following error and was prevented from using the password:
Try to avoid common words.
As far as I know, this string is not a common word in any language so I started to dig into it deeper to see why this password was not allowed.
The fresh installation is still using the default pam_unix module to validate changed passwords, so I looked in: /etc/pam.d/common-password , and did not see any rules that would make this password invalid.
I then started trying slight variations of the same password to dig a little deeper into why the random password was not allowed. I started to find slightly different variations of the password that were also not valid:
It seems as though there is a regular expression set somewhere that is preventing me from using a lot of passwords which should be valid.
This only occurs when attempting to set the password from the change password option in the top right drop down.
Changing the password via the terminal using passwd still allows the password change.
Does anyone have any idea as to what I should check next to be able to determine why these passwords are not valid?