Find similar vulnerabilities and bugs across codebases using pattern-based analysis.

Author: Axel Mierczuk

Use this skill when you need to:

• Hunt for bug variants after finding an initial vulnerability
• Build CodeQL or Semgrep queries from a known bug pattern
• Perform systematic code audits across large codebases
• Analyze security vulnerabilities and find similar instances
• Create reusable patterns for recurring vulnerability classes

This skill provides a systematic five-step process for variant analysis:

1. Understand the original issue - Identify root cause, conditions, and exploitability
2. Create an exact match - Start with a pattern matching only the known bug
3. Identify abstraction points - Determine what can be generalized
4. Iteratively generalize - Expand patterns one element at a time
5. Analyze and triage - Document and prioritize findings

Includes:

• Tool selection guidance (ripgrep, Semgrep, CodeQL)
• Critical pitfalls to avoid (narrow scope, over-specific patterns)
• Ready-to-use templates for CodeQL and Semgrep in Python, JavaScript, Java, Go, and C++
• Detailed methodology documentation

/plugin install trailofbits/skills/plugins/variant-analysis

• codeql - Primary tool for deep interprocedural variant analysis
• semgrep - Fast pattern matching for simpler variants
• sarif-parsing - Process variant analysis results