Application security, or software security, focuses on building software features that are secure. This doesn’t necessarily have anything to do with security features.

To create secure features, we need to manage our software development activities in a security-focused risk management framework, train our developers, and apply the following best practices:

1. Perform static code analysis using a security-savvy tool
2. Perform threat modeling (sometimes called risk analysis)
3. Perform penetration testing
4. Perform risk-based security testing
5. Use abuse cases
6. Integrate security requirements
7. Co-operate with operations

When all these activities are nicely integrated into the software development lifecycle, a Security Development Lifecycle (SDL) results. Ideally, the SDL should be informed by an organizational security policy.

See also my posts on Application Security.