How The NSA Secures Computers
An Anonymous Reader wrote to mention an NSA site covering secure configuration guidelines for a number of operating systems. From the site: "NSA initiatives in enhancing software security cover both proprietary and open source software, and we have successfully used both proprietary and open source models in our research activities. NSA's work to enhance the security of software is motivated by one simple consideration: use our resources as efficiently as possible to give NSA's customers the best possible security options in the most widely employed products."
... but there are also a few guides to the applications security available: http://www.nsa.gov/snac/downloads_all.cfm
my favorite are Cisco IOS and Microsoft CA guides
The NSA has released it's over version of linux, SELinux, the Security Enhanced Linux.
SecureThe.Net - Practical Resources for Securing Systems
"BSD: Free as in speech. Linux: Free as in beer. Windows 10: Free as in herpes." --Man On Pink Corner in #52607549.