SAST vs DAST vs (IAST/RASP): Quick AppSec Checklist

Source: Dev.to

Overview

If you work in application security or do code reviews, you’ve probably heard the acronyms SAST, DAST, IAST, and RASP. They solve different problems and fit into different stages of the software development lifecycle (SDLC). Below is a practical breakdown to help you choose the right tool for the job.

SAST (Static Application Security Testing)

• What it does: Analyzes source code or binaries without running the application.
• When to use: Early in development (IDE, CI pipelines).
• Strengths: Good for catching common issues such as injection flaws, insecure logic, and misuse of APIs.
• Trade‑offs: May produce false positives and has limited runtime context.

DAST (Dynamic Application Security Testing)

• What it does: Tests a running application from the outside.
• When to use: Works well against production‑like environments.
• Strengths: Finds real, exploitable issues such as authentication flaws, misconfigurations, and runtime injection bugs.
• Trade‑offs: Limited visibility into the source code.

IAST / RASP (Interactive/Application Security Testing & Runtime Application Self‑Protection)

• What it does: Runs inside the application at runtime, combining code‑level insight with real execution data.
• When to use: Useful for high‑confidence findings and production monitoring.
• Strengths: Provides runtime visibility and can offer protection against attacks.
• Trade‑offs: Requires instrumentation and adds runtime overhead.

Choosing the Right Tool

There’s no single “best” option. Most mature security programs combine:

• SAST for early feedback.
• DAST for real‑world attack simulation.
• IAST/RASP for runtime visibility and protection.

Secure Coding Practices Checklist

A concise checklist that compares these approaches, explains where they fit best, and highlights common mistakes when relying on only one tool.

Secure Coding Practices Checklist

If you’re doing code reviews, threat modeling, or building AppSec pipelines, this checklist should save you time and help you pick the right tool for each phase.