Bitsquatting: DNS hijacking without exploitation
I'm surprised that registering domain names a bit-flip away from a popular one will get you a bunch of traffic!
Apache SSLPolicy Directive
Makes configuring SSL simple by enabling a whole set of security policy directives in one command.
Apache includes policies from the Mozilla organization, including the most secure option: "modern"
2025-07-29 update: SSLPolicy is only in Apache 2.5.0 or later. It's currently not even in Debian Sid :-(
OWASP Security Cheat Sheets
Cheet sheets on all kinds of security, from C-based toolchain hardening to HTTP headers.
Stack Overflow Definitive Guide to Form-based Website Authentication
A really nice guide to the best, most secure ways to do website authentication. Lots of nice links