What is the overall goal of software security testing?

Identifying key security features describes a requirements or design analysis activity, not the primary goal of security testing, which focuses on finding weaknesses rather than cataloging existing protections.

Ensuring all software functions perform as specified describes functional or acceptance testing, not security testing, which is specifically concerned with how software behaves under adversarial or unexpected conditions.

The overarching goal of software security testing is to reduce vulnerabilities within a software system by systematically identifying flaws such as injection weaknesses, authentication bypasses, or insecure configurations. By finding and remediating these vulnerabilities, security testing lowers the risk of exploitation and improves the overall security posture of the application. This distinguishes it from functional testing, which verifies behavior, rather than proactively hardening the system against attack.

Making software development more agile describes a process methodology goal (e.g., Agile or DevSecOps adoption) and is unrelated to the technical objective of security testing itself.