We have clean CentOS 5.6 setup and virtualmin on it, that's all. What type of security steps would you suggest are appropriate?
http://www.wiredtree.com/supportservices/servershield.php this page have a good summary of checklists i think. which steps on these are required to do? or do you have better suggestions rather then those security hardenings:
(Esspecially ddos and brute force attack protection is a problem it seems)
Firewall Protection: APF – Configure both ingress and egress firewall protection. BFD – Detect and prevent brute force attacks. CPHulk – Detect and prevent brute force attacks. HTTP Intrusion and DOS Protection: Mod_security – Install and configure mod_security for Apache with auto-updating ruleset. Mod_evasive – Install and configure DOS, DDOS, and brute force detection and suppression for Apache. PHP SuHosin – PHP Hardening through the Hardened PHP Project. Available on request. Server Hardening: Disable IP Source Routing – Enable protection against IP source route attacks. Disable ICMP Redirect Acceptance – Enable protection against ICMP redirect attacks. Enable syncookie protection – Enable protection against TCP Syn Flood attacks. Enable ICMP rate-limiting – Enable protection against ICMP flood attacks. Harden host.conf – Enable spoofing protection and protection against DNS poisoning attacks. Harden Apache – Prevent module and version disclosure information. Harden SSH – Allow only SSH version 2 connections. Harden Named – Enable protection against DNS recursion attacks. Ensure Filesystem Permissions – Fix permission on world writable directories and prevent against directory-transversal attacks. Harden temporary directory and shared memory locations – Enforce noexec, nosuid on tmp and shm mounts. Harden “fetching” utilities - Allows root-only access of wget, curl, and other utilties often used in web-based attacks. Remove unnecessary packages – removes RPMS which are not needed to prevent against potential vulnerabilities and free up disk space. Disable unused services – Disable services which are not used. Disable unneeded processes – Disable processes which are not needed for server operation. PAM Resource Hardening – Protects against exploits which use core dumps and against user resource exhausting through fork bombs and other shell attacks. PHP Hardening – Enable OpenBaseDir protection. Security Audits: Rootkit Hunter – Nightly scan to detect system intrusions. Chkrootkit – Nightly scan to detect system intrusions. Nobody Process Scanner – Scans for unauthorized "nobody" processes.