Enforcing Password Quality

Installation

sudo apt install libpam-pwquality

Configuration

Passwords must be at least 8 characters long, include at least one uppercase letter, one lowercase letter, and one digit, this policy is enforced only for local users.

sudo sed -i 's/^[#[:space:]]*minlen[[:space:]]*=.*/minlen = 8/' "/etc/security/pwquality.conf"
sudo sed -i 's/^[#[:space:]]*dcredit[[:space:]]*=.*/dcredit = -1/' "/etc/security/pwquality.conf"
sudo sed -i 's/^[#[:space:]]*ucredit[[:space:]]*=.*/ucredit = -1/' "/etc/security/pwquality.conf"
sudo sed -i 's/^[#[:space:]]*lcredit[[:space:]]*=.*/lcredit = -1/' "/etc/security/pwquality.conf"
sudo sed -i 's/^[#[:space:]]*minclass[[:space:]]*=.*/minclass = 3/' "/etc/security/pwquality.conf"
sudo sed -i 's/^[#[:space:]]*enforcing[[:space:]]*=.*/enforcing = 1/' "/etc/security/pwquality.conf"
sudo sed -i 's/^[#[:space:]]*local_users_only[[:space:]]*$/local_users_only/' "/etc/security/pwquality.conf"