What is variant analysis in security research?

Variant analysis is the process of taking a known vulnerability and searching for other instances of that same bug or similar patterns across an entire codebase to ensure a complete fix.

Which tools does the variant-analysis skill use?

The skill provides guidance for using ripgrep for quick searches, Semgrep for syntax-aware pattern matching, and CodeQL for deep interprocedural data flow and taint analysis.

When should I use this skill instead of a regular code review?

Use this skill specifically after an initial vulnerability has been identified. It is designed to hunt for 'siblings' of a known bug rather than performing a general, unfocused audit.

How does the skill minimize false positives?

It follows an iterative generalization process, recommending that users change only one element of a pattern at a time and stop once the false positive rate exceeds approximately 50%.

Security Variant Analysis

Name: Security Variant Analysis
Author: trailofbits

bytrailofbits

•

939

•

Security & Testing

Identifies similar vulnerabilities and bugs across codebases using systematic pattern-based analysis and advanced security tool integration.

The Variant Analysis skill enables security researchers and developers to perform exhaustive bug hunting by identifying 'variants' of a known vulnerability throughout a repository. By following a rigorous five-step methodology—moving from an exact code match to an abstracted semantic pattern—this skill helps uncover hidden instances of a bug that simple searches might miss. It provides strategic guidance on when to use tools like ripgrep, Semgrep, and CodeQL, ensuring that once a root cause is identified, it is completely eradicated across the entire codebase rather than just patched in a single location.

Key Features

01Structured triage templates for documenting exploitability and priority

02Pattern abstraction guidance to balance precision and recall

03Deep integration with Semgrep, CodeQL, and ripgrep for multi-layer analysis

04939 GitHub stars

05Systematic five-step generalization workflow for security bug hunting

06Cross-functional data flow tracking and taint analysis support

Use Cases

01Analyzing how a shared root cause manifests across different modules or languages

02Developing and refining custom Semgrep or CodeQL rules for specific security patterns

03Scaling a single vulnerability discovery into a comprehensive codebase audit

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add trailofbits/skills variant-analysis

For use in Claude.ai and ChatGPT

Download Skill