The Synergy of Combined Testing

The Synergy of Combined Testing

When properly orchestrated, SAST, DAST, and IAST create synergies that multiply their individual values. SAST identifies vulnerabilities early when they're cheapest to fix, DAST validates that deployed applications resist attack, and IAST provides runtime accuracy that confirms or refutes findings from other tools. This layered approach catches vulnerabilities that might slip through any single testing method while providing multiple validation points that increase confidence in results.

Consider how each tool complements the others in detecting SQL injection. SAST identifies potentially vulnerable code patterns where user input reaches database queries. DAST attempts actual injection attacks to confirm exploitability. IAST observes whether input actually reaches queries without sanitization during testing. When all three identify the same vulnerability, confidence is absolute. When findings differ, investigation reveals important context—perhaps SAST flagged code that framework protections secure, or DAST missed a vulnerability only triggered under specific conditions that IAST observed.

The combination also addresses each tool's individual weaknesses. SAST's false positives are validated or refuted by runtime testing. DAST's limited code coverage is supplemented by SAST's complete analysis. IAST's dependency on test execution is complemented by SAST's static coverage and DAST's systematic probing. Together, they provide both breadth and depth of security analysis throughout the development lifecycle.