Passwor Policy Implementation
@@@@@@@@@@@@@@@@@@@@@@@@
1. Create a backup
@@@@@@@@@@@@@@@@@@@@@@@@

Change directory to /etc/pam.d/

  $ cd /etc/pam.d/

Use ll command to list

  $ ll

Backup common-password file using cp command

  $ sudo cp common-password common-password.backup

@@@@@@@@@@@@@@@@@@@@
2. Password Length
@@@@@@@@@@@@@@@@@@@@

Use your favorite editor to edit the common-password file

  $ sudo vim common-password

Locate the line starting with success and add minlen=7 at the end of the line

   Save and exit file

@@@@@@@@@@@@@@@@@@@@@@@
3. Password Complexity
@@@@@@@@@@@@@@@@@@@@@@@

Install the libpam-pwquality package

  $ sudo apt-get install libpam-pwquality

Open and edit the common-password file

  $ sudo vim common-password

You may add the following complexities

  

password        requisite                       pam_pwquality.so retry=3  Ucredit=-1
password        requisite                       pam_pwquality.so retry=3  Dcredit=-1
password        requisite                       pam_pwquality.so retry=3  Ocredit=-1

Ucredit=-1 for uppercase
  Dcredit=-1 for lowercase
  Ocredit=-1 for special character

  Save and Exit file

@@@@@@@@@@@@@@@@@@@@@@@@
4. Password Expiration
@@@@@@@@@@@@@@@@@@@@@@@@

   $ cd /etc

Create a backup using the cp command

   $ sudo cp login.defs login.defs.backup

Edit the login.defs file

    $ sudo vim login.defs

Search for the PASS_MAX_DAYS and change it to your prefered time/number of days.

    Save and exit file. 

@@@@@@@@@@@@@@@@@@@@@@@@@@@@
5. Verify the set policies
@@@@@@@@@@@@@@@@@@@@@@@@@@@@

Users are located in the directory /etc/passwd

Add user 
  $ sudo adduser test

Check if the user was added
  $ cat /etc/passwd

To check password policies for each user, run the command 
    
   $ sudo chage -l test

To effect changes on exixting users
 we use sudo chage –expiredate (date –d +90days +%y-%m-%d)

   $ sudo chage -d 2024-03-03 test
   $ sudo chage -E 12/04/2024 -M 90 -W 7 test

To revert the expiry policy for each user
   $ sudo chage -E -1 test