1.Linux Operating Systems Security Tuning Its very essential to secure your Linux operating system since its where all your applications run. What we can do : 1. Review User Accounts 2. Review the policies implemented 3. Review File Systems Permissions 4. Review your Operating Systems Services. 2.Host Intrusion Detection Operating Systems Host intrusion detection is used to investigate suspected or unusual activities by looking for changes in the system files, checking /analyzing the logs, keep track of installed software and running services. Some of the open source HIDs we currently support: a. OSSEC b. OpenDLP c. AIDE d. SAMHAIN 3.Hardening We use multiple tools and scripts to lock-down or harden your Linux operating system and enhance it's security.Configuring your OS security will decrease it's susceptibility to compromises. 4.SELinux. Security-Enhanced Linux (SELinux) is a kernel security module which used to enhance existing security solutions.In short it can help protect you from bugs in your applications.