a) http://www.lids.org/about.html

b) http://selinux.sourceforge.net/

c) apt-cache search harden

bastille – Security hardening tool

harden – Makes your system hardened

harden-clients – Avoid clients that are known to be insecure

harden-development – Development tools for creating more secure programs

harden-doc – Useful documentation to secure a Debian system

harden-environment – Hardened system environment

harden-nids – Harden a system by using a network intrusion detection system

harden-remoteaudit – Audit your remote systems from this host

harden-servers – Avoid servers that are known to be insecure

harden-surveillance – Check services and/or servers automatically

harden-tools – Tools to enhance or analyze the security of the local system