Security Sites [SANS' Information Security Reading Room http://www.sans.org/rr/] — not specifically Linux, but tons of advanced reading here. Lists hosted/followed by insecure.org [The whole shebang http://lists.insecure.org/] — got an itch? Get it scratched here. [Full Disclosure archives http://lists.insecure.org/lists/fulldisclosure/] — rough, uncut, uncensored real-time security information. The [Bugtraq list http://www.securityfocus.com/archive/1] — run by [Secuity Focus http://www.securityfocus.com/]. [Crypto-Gram http://www.counterpane.com/crypto-gram.html] — Bruce Schneier's monthly newsletter. [CVE http://cve.mitre.org/] — the Common Vulnerabilities and Exposures list. A community effort to provide a common catalog (and name!) for security vulnerabilities.