Linux OS Hardening

• Password policy (/etc/shadow, /etc/login.defs, /etc/pam.d/system-auth)
• Enable firewall (iptables/firewalld)
• firewall-cmd --help and /etc/firewalld directory
• Enable SELinux
• Secure Enhanced Linux. Uses the linux security module (LSM)
• Establish the access and permission rights for every user, app, processes, etc
• sestatus
• /etc/sysconfig/selinux configuration file