Why API testing matters
APIs now power web, mobile, and device experiences. The 2023 OWASP API Security Top 10 shows how design issues—broken object authorization, unrestricted resource consumption, and weak inventory—remain leading causes of breaches. SAST brings these risks to light from the specification itself, keeping exposure low and engineering speed high.
Add SAST early in design to avoid emergency fixes and reduce downstream DAST noise. Pair this guide with the API security scanner overview for runtime considerations.
Key vulnerabilities found by SAST
- Broken authentication: missing security schemes on endpoints, unscoped tokens, and optional auth that should be mandatory.
- Broken authorization: no role or scope mapping, missing path parameter validation, and unbounded object access.
- Sensitive data exposure: returning PII fields without masking or using plaintext transport.
- Error-handling flaws: verbose stack traces, missing RFC 7807 structure, inconsistent status codes.
- Availability issues: absent pagination, rate limiting headers, or request size limits that enable scraping and abuse.
Step-by-step SAST testing workflow
- Collect the latest OpenAPI or Swagger spec. Ensure version and servers fields are accurate.
- Run APISAST locally or via CI. Choose the comprehensive profile for high-risk services.
- Review findings grouped by severity with rule IDs and OWASP mapping.
- Patch the specification: add missing auth, tighten schemas, and align error responses to RFC 7807.
- Re-run to confirm fixes and export the report for auditors.
Need a template to start? Visit the API security SAST tools page.
Integrating SAST into DevOps
CI/CD hooks
Block merges when high-severity issues are found. Store artifacts for audit trails.
Branch policies
Require an updated spec per feature branch to keep inventory current.
Add a nightly job that scans all service specs and posts deltas to Slack. This keeps teams aware of regressions without slowing daily development.
FAQs about SAST for APIs
Do I need source code?
No. APISAST works directly on OpenAPI/Swagger definitions so platform teams can evaluate third-party services, too.
How often should I run scans?
On every pull request and nightly across all published specs to prevent drift.
What about GraphQL?
GraphQL support is available through schema-to-OpenAPI transformations; see API security scanner for details.
Next steps
Start with the home page to upload a spec, then deepen your program with API security scanner and OpenAPI security scanner resources. For tactical rollout, pair this guide with your CI templates so enforcement is automatic.