Every vibrant technology marketplace needs an unbiased source of information on best practices as well as an active body advocating open standards. In the Application Security space, one of those groups is the Open Web Application Security Project (or OWASP for short).
The Open Web Application Security Project (OWASP) is a 501(c)(3) worldwide not-for-profit charitable organization focused on improving the security of software. Our mission is to make software security visible, so that individuals and organizations are able to make informed decisions. OWASP is in a unique position to provide impartial, practical information about AppSec to individuals, corporations, universities, government agencies and other organizations worldwide. Operating as a community of like-minded professionals, OWASP issues software tools and knowledge-based documentation on application security.
The entire Open Web Application Security Project (OWASP) Testing Guide v3 can be downloaded here