SAST

Static Application Security Testing (SAST) is a security testing methodology that analyzes source code, bytecode, or binaries for security vulnerabilities without executing the application. SAST tools examine the static code to identify potential security flaws, coding errors, and compliance violations.

How SAST Works

SAST tools perform deep analysis of application source code by parsing the code and creating an abstract syntax tree (AST) or control flow graph. The tools then analyze these representations to identify patterns that match known security vulnerabilities, such as SQL injection, cross-site scripting (XSS), buffer overflows, and insecure cryptographic implementations.

Key Characteristics

• White-box Testing: SAST has access to source code and internal structure
• Early Detection: Identifies vulnerabilities during development phase
• Comprehensive Coverage: Analyzes all code paths, including unreachable code
• Fast Execution: Runs without requiring application runtime
• Precise Location: Pinpoints exact lines of code where vulnerabilities exist

Common Vulnerabilities Detected

• Injection Flaws: SQL injection, command injection, LDAP injection
• Cross-Site Scripting (XSS): Reflected, stored, and DOM-based XSS
• Buffer Overflows: Memory corruption vulnerabilities
• Insecure Deserialization: Object deserialization security issues
• Cryptographic Issues: Weak algorithms, improper key management
• Authentication/Authorization: Broken authentication mechanisms
• Input Validation: Improper validation of user inputs
• Security Misconfigurations: Insecure default configurations

Benefits

• Early Detection: Finds vulnerabilities before code reaches production
• Cost-Effective: Reduces cost of fixing security issues
• Comprehensive Coverage: Analyzes entire codebase systematically
• Developer Feedback: Provides detailed information for developers
• Integration: Can be integrated into CI/CD pipelines
• Compliance: Helps meet security and compliance requirements

Limitations

• False Positives: May report issues that are not actual vulnerabilities
• Runtime Context: Cannot detect vulnerabilities that occur at runtime
• Configuration Issues: May miss configuration-related security issues
• Third-Party Components: Limited ability to analyze external dependencies
• Complex Logic: May miss business logic vulnerabilities

Popular SAST Tools

• SonarQube: Multi-language static analysis platform
• Checkmarx: Commercial SAST solution
• Veracode: Cloud-based static analysis
• Fortify: Static code analysis by Micro Focus
• Semgrep: Fast, pattern-based static analysis
• Bandit: Security linter for Python
• ESLint: JavaScript/TypeScript linting with security plugins
• Brakeman: Security scanner for Ruby on Rails

Best Practices

• Integrate Early: Integrate SAST tools from the beginning of development
• Custom Rules: Create custom rules for organization-specific issues
• False Positive Management: Establish process for triaging false positives
• Developer Training: Train developers on secure coding and SAST tools
• CI/CD Integration: Integrate SAST into continuous integration pipelines
• Regular Updates: Keep SAST tools and rules updated
• Thresholds: Set appropriate security thresholds for builds

SAST vs Other Testing Methods