variant-analysis
💡 Summary
A systematic methodology and tooling guide for performing variant analysis to find similar vulnerabilities across codebases.
🎯 Target Audience
🤖 AI Roast: “It's a great guide for finding more bugs, but it won't write the perfect query for you—that's still on you, human.”
Risk: The skill guides creation of code queries which, if poorly written, could lead to false positives/negatives, misdirecting security efforts. Mitigation: Always validate generated patterns against a controlled test suite before broad deployment.
Variant Analysis
Find similar vulnerabilities and bugs across codebases using pattern-based analysis.
Author: Axel Mierczuk
When to Use
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
What It Does
This skill provides a systematic five-step process for variant analysis:
- Understand the original issue - Identify root cause, conditions, and exploitability
- Create an exact match - Start with a pattern matching only the known bug
- Identify abstraction points - Determine what can be generalized
- Iteratively generalize - Expand patterns one element at a time
- 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
Installation
/plugin install trailofbits/skills/plugins/variant-analysis
Related Skills
codeql- Primary tool for deep interprocedural variant analysissemgrep- Fast pattern matching for simpler variantssarif-parsing- Process variant analysis results
Pros
- Provides a clear, structured methodology for a complex task.
- Offers practical templates for major analysis tools (CodeQL, Semgrep).
- Helps avoid common pitfalls in pattern generalization.
Cons
- Heavily reliant on user's ability to craft accurate queries.
- More of a guide/framework than an automated tool.
- Requires significant security and code analysis expertise to use effectively.
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