semgrep-rule-creator

To create custom Semgrep rules for security vulnerabilities, use a test-driven approach by writing vulnerable and safe test cases first, crafting the pattern or taint-mode rule, and iterating until tests pass.

Taint analysis in Semgrep rule creation tracks data flow from sources to sinks, enabling precise detection of vulnerabilities like SQL injection while minimizing false positives compared to basic pattern matching.

Yes, you need Semgrep installed locally to validate custom rules, run test cases against vulnerable and safe code snippets, and iterate on pattern matching or taint-mode configurations until successful.

The best way to reduce false positives in static analysis rules is prioritizing taint-mode tracking over generic pattern matching, leveraging AST analysis for accurate syntax matching, and validating with comprehensive test cases.

AST analysis helps match bug patterns in source code by parsing the abstract syntax tree, allowing you to define precise structural patterns that Semgrep uses to identify complex security vulnerabilities.

Writing test cases before creating a Semgrep rule ensures comprehensive coverage by defining expected vulnerable and safe behaviors upfront, guiding the AST pattern or taint-mode development, and verifying detection accuracy iteratively.