Why Codex Security Doesn't Provide SAST Reports

SAST (Static Application Security Testing) is effective at finding vulnerabilities by tracking data flow, but its limitations become clear in complex codebases. In particular, what matters more than whether data reaches its destination is whether the security validation implemented in the code actually guarantees the safety of the real system.

For example, even if a specific function calls sanitize_html(), it is difficult to determine whether that function is sufficient for the current rendering context or encoding method. Also, order-of-operations issues, such as performing a regex check before URL decoding, are hard to catch through simple data flow tracking alone.

Codex Security addresses this problem by first analyzing the repository's own architecture and intended behavior, rather than simply taking in and classifying SAST reports.

Their approach is as follows:

• Verifying the effectiveness of security validation: Instead of treating security validation or sanitization as a simple pass-through item, it tries to understand what the code intends to guarantee and then attempts to falsify it.
• Context-based analysis: Like a security researcher, it reads the context of the entire repository to find discrepancies between the code's intent and its actual implementation.
• High-signal delivery: By verifying issues in an isolated environment, it reduces analysis fatigue for security teams and provides highly reliable issues.