What Is IAST (Interactive Application Security Testing)?

Interactive Application Security Testing (IAST) is a method that blends SAST (Static Application Security Testing) and DAST (Dynamic Application Security Testing) to find application vulnerabilities more effectively.

The IAST characteristics include:

• IAST tools work by adding sensors or monitoring components inside the application while it runs. These tools watch how the app behaves during testing, whether tests are automated or done by people. This approach lets IAST check code execution, user inputs, and how the app handles data in real time.
• IAST does not scan the entire codebase automatically; its coverage is determined by the breadth of the application exercised during tests. The more extensive the test activity, the deeper the vulnerability coverage.
• IAST is typically deployed in QA or staging environments where automated or manual functional tests are run.

Why IAST Matters in Cybersecurity

SAST analyzes source code, bytecode, or binaries without running the application and is highly effective at uncovering coding errors, but it can produce false positives and miss runtime-specific issues.

DAST tests applications from the outside as they run and can expose issues that only appear at runtime, but lack deep visibility into internal logic or code structure. IAST bridges the gap by combining the strengths of these techniques, providing:

• Deeper insights into vulnerability sources and paths.
• Improved detection accuracy compared to SAST or DAST alone.
• Reduction of false positives by correlating runtime activity with code analysis.

How IAST Works

• Instrumentation: IAST uses instrumentation, meaning sensors or monitoring code are embedded into the application (often in a QA or staging environment) to observe its behavior during testing.
• Monitoring :It observes data flow, user input, and code behavior in real-time as the application is exercised by tests or manual actions.
• Detection : it flags vulnerabilities such as insecure configuration, unsanitized data flows, or injection risks.
• Reporting : Actionable findings and remediation guidance are provided to developers to address detected issues.

Example

During functional testing, the QA team interacts with the login form. The IAST tool detects that user input flows into a database query without sanitization, indicating a potential SQL injection risk. The team receives a vulnerability report and actionable steps to fix the security issues.

Related Terms

• SAST (Static Application Security Testing)
• DAST (Dynamic Application Security Testing)
• SCA (Software Composition Analysis)
• Application Security Testing
• ASPM (Application Security Posture Management)