What Is SAST (Static Application Security Testing)?

SAST is a type of application security testing that checks an application’s source code (the original code written by developers), dependencies (external libraries or packages the code relies on), or binaries (compiled code ready to run) before it runs. This approach is often called white-box testing because it examines the internal logic and structure of the code for vulnerabilities and flaws, rather than testing just the application’s behavior from the outside.

Why SAST Matters in Cybersecurity

Securing code is a key part of DevSecOps. SAST helps organizations find vulnerabilities like SQL Injection, Cross-Site Scripting (XSS), weak encryption, and other security issues early in the Software Development Lifecycle. This means teams can fix problems faster and at a lower cost.

How SAST Works

• Analyze source code, binaries, or bytecode without executing them.
• Identifies vulnerabilities in coding practice (eg, missing validation, exposed API key)
• Integrate into the developer workflow (CI/CD)
• Generate a report in vulnerabilities that were found and provide guidance on how to solve them (remediation)

Common Vulnerabilities found by SAST

• SQL Injection
• Cross-site scripting (XSS)
• Use of Insecure cryptographic algorithms (e.g., MD5, SHA-1)
• Exposed API key credentials in the hardcoded
• Buffer overflow
• Validation error

Benefits of SAST

• Cheaper cost : fixing vulnerability issues early is less expensive than post-deployment
• Early detection: finds security issues during development.
• Compliance support : align with standards like OWASP, PCI DSS, and ISO 27001.
• Shift-left security : integrate security into the development workflow from the beginning
• Developer-friendly: Provide the developer with actionable steps to fix security issues.

Example

During a SAST test, the tool finds security issues where developers use insecure MD5 to hash passwords. The SAST tool flags it as a vulnerability and suggests replacing MD5 with bcrypt or Argon2, which are stronger algorithms compared to MD5.

Related Terms

• DAST (Dynamic Application Security Testing)
• IAST (Interactive Application Security Testing)
• SCA (Software Composition Analysis)
• SSDLC
• DevSecOps