SAST vs DAST vs IAST: Choosing the Right Security Testing for Each Stage

Choosing the Right Security Testing

Static (SAST), Dynamic (DAST), and Interactive (IAST) security testing each have distinct strengths and limitations. Understanding when to use each approach, and how to combine them, is key to comprehensive coverage.

Comparison

SAST (Static Application Security Testing)

How it works: Analyzes source code without executing the application.

Strengths:

• Tests early in development (shift-left)
• Full code coverage
• Identifies exact code location of issues
• Fast execution on code changes

Weaknesses:

• High false positive rates (20-40%)
• Cannot find runtime vulnerabilities
• Language/framework-specific
• Cannot test deployed configurations

DAST (Dynamic Application Security Testing)

How it works: Tests the running application via HTTP requests.

Strengths:

• Finds runtime vulnerabilities
• Technology agnostic (tests HTTP)
• Lower false positives
• Tests deployed configuration

Weaknesses:

• Cannot identify exact code location
• Coverage depends on crawling effectiveness
• Slower execution
• May miss authenticated paths without configuration

IAST (Interactive Application Security Testing)

How it works: Agent inside the application observes behavior during testing.

Strengths:

• Real-time analysis during functional testing
• Low false positives (observes actual execution)
• Maps vulnerabilities to exact code lines
• Understands data flow through application

Weaknesses:

• Requires agent deployment
• Language-specific agents
• Only tests executed code paths
• Can impact application performance

When to Use Each

Optimal Combination

Use all three for maximum coverage:

1. SAST in CI/CD for every code change
2. IAST during QA/functional testing
3. DAST against staging/production deployments

SuperClue Testing Suite

SuperClue provides DAST scanning with 350 modules, complementing your SAST and IAST tools for comprehensive application security coverage.