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Static Application Security Testing (SAST)

Static Application Security Testing (SAST) is a method of analyzing application source code or binaries before execution to detect security vulnerabilities early in the development lifecycle.

What is SAST?How it typically works?Common techniquesImpactFurther reading

What is SAST?

SAST examines an application’s code without running it, a practice often referred to as white-box testing. By reviewing source code, bytecode, or binaries, it identifies potential vulnerabilities such as SQL injection, cross-site scripting (XSS), and buffer overflows before the application is deployed. For SecOps and development teams, SAST is valuable because it shifts security left, integrating vulnerability detection into the development process instead of waiting until after deployment.

How it typically works?

  1. Code ingestion: the SAST tool scans source code, intermediate code, or binaries.
  2. Parsing and modeling: it creates an internal representation of the code, mapping data flows, control structures, and dependencies.
  3. Pattern analysis: the tool looks for known insecure coding patterns, such as unsanitized input being passed into database queries.
  4. Data flow analysis: more advanced tools trace how data moves through the application to detect flaws that span multiple functions.
  5. Reporting: results are presented with vulnerability details, severity levels, and remediation advice.

SAST can be integrated into CI/CD pipelines, providing developers with immediate feedback during builds. This helps teams remediate issues before they ever reach production, improving both security and development efficiency.

Common techniques

  • Pattern matching: checks code against libraries of known insecure coding practices.
  • Data flow analysis: traces how input data propagates through an application.
  • Control flow analysis: evaluates program logic to detect unreachable or insecure code.
  • Semantic analysis: examines meaning and relationships in the code to catch logic flaws.
  • IDE integration: SAST tools often integrate directly into developer environments for real-time feedback.
  • Cloud-based SAST: enables scalable scanning of large codebases in modern pipelines.

Impact

SAST reduces the cost of remediation by finding vulnerabilities during development, where they are cheaper to fix. It also ensures compliance with security standards such as OWASP Top 10, PCI DSS, and ISO 27034.

However, SAST tools are prone to false positives and may struggle with very large or complex codebases. To be effective, results must be triaged and prioritized. For SecOps, SAST is one part of a broader AppSec strategy that should also include dynamic and runtime testing.

Further reading

Related topics

DASTSCASecure Coding Practices