Why Codex Security Doesn’t Include a SAST Report

Codex Security deliberately avoids starting its analysis with Static Application Security Testing (SAST) reports because the hardest vulnerabilities often stem from flawed security assumptions rather than simple dataflow tracking. SAST models struggle to confirm if a supposed defense, like a sanitizer, is truly sufficient given the specific rendering context or subsequent transformations. Codex Security instead begins by analyzing the repository's architecture and intent, then validates findings by reasoning about the entire transformation chain, often using techniques like micro-fuzzing or formalization with solvers like z3. Starting with a SAST report risks premature narrowing of focus, introducing hard-to-unwind implicit assumptions, and obscuring the agent's own analytical contributions. The goal is to move beyond merely identifying a check to proving whether the underlying invariant holds, focusing on complex issues like order-of-operations mistakes and state/invariant problems that pure source-to-sink analysis misses.

(Source：OpenAI)