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Yara Rule Authoring

Listed
trailofbits·vlatest·security·CC-BY-SA-4.0

This skill helps you craft precise YARA rules for malware detection by providing a user-friendly interface and guidance.

Repository

Install on your platform

Showing Claude Code. One command installs this skill into any of the agents below.

  1. 1

    Run this in your project

    terminal
    $ npx skills add trailofbits/skills --skill yara-rule-authoring -a claude-code

  2. Uses the open-source skills CLI and needs Node.js. Add -g to install it for your user instead of this project.

What we know about this skill

Publisher

trailofbits

Taken from the source listing. We haven't verified who controls this account.

Install target

Live repository

Not pinned. Installing fetches whatever the repository holds at the time you run the command.

No human has reviewed this code. The checks below are a static scan of the files at one commit — nobody has run this skill or judged whether it works. A skill runs with whatever access you give your agent, so read the source before you install it.

Automated safety checks

scanned

This skill failed 1 of 6 checks. A failure is not proof of bad intent; it means something in the code needs a human to look at it before you run it.

  • No credential access: failed

    Touches credential material in 3 places.

    Neither the code nor the SKILL.md instructions read SSH keys, cloud credentials, keychains, token stores, browser cookie databases or dotfiles that hold secrets.

    What it found

    • plugins/yara-authoring/skills/yara-rule-authoring/references/strings.md:409SSH private keys or config
      $cred_path = /\.(npmrc|env|ssh\/id_rsa|aws\/credentials)/
    • plugins/yara-authoring/skills/yara-rule-authoring/references/strings.md:422browser cookie or password store
      $firefox_logins = "logins.json"
    • plugins/yara-authoring/skills/yara-rule-authoring/references/strings.md:426SSH private keys or config
      $ssh_key = /\.ssh\/(id_rsa|id_ed25519)/

  • Declares what it does: passed

    SKILL.md parses and declares a name and a description.

    SKILL.md exists, its frontmatter parses, and it declares a name and a description.

  • No undeclared network calls: passed

    Makes no network calls.

    Every host the skill dials — from its scripts, its config endpoints or the commands it tells the agent to run — is either well-known package and API infrastructure or declared in its own frontmatter. Links in documentation are not counted.

  • No obfuscated payloads: passed

    No encoded or obfuscated payloads.

    No base64, hex or compressed blob is decoded and then executed, and no encoded shell commands.

  • No pipe-to-shell installers: passed

    No pipe-to-shell or download-and-run installers.

    No `curl … | sh` pattern, in the code or in the instructions, that runs code fetched at run time.

  • Pinned to a commit: passed

    Scanned trailofbits/skills at 82fe822625.

    The exact upstream commit SHA that was scanned is recorded, so the result refers to specific bytes.

Commit
82fe822625
Manifest
plugins/yara-authoring/skills/yara-rule-authoring/SKILL.md
Scanned
14 files, 4,628 lines
This is a static scan, not a review. It reads the skill's files; it does not run them, and it cannot tell you whether the skill is any good or whether the code does what its description says. A skill runs with whatever access you give your agent.
What each check looks for →

About this skill

What it does

This skill enables AI agents to author YARA rules, which are used for identifying and detecting malicious software or patterns in binary files. It provides guidance on creating accurate and efficient rules using YARA syntax, including the use of wildcards, keywords, and hexadecimal patterns.

When to use it

  • You need to create custom YARA rules for malware analysis or threat hunting.
  • You want to automate the detection of known malicious indicators in network traffic or file systems.
  • You are working on a security operations team and require tailored rules for specific threats.

Key capabilities

  • Generating YARA rules based on provided patterns or samples
  • Explaining YARA syntax, including strings, conditions, and metadata
  • Offering best practices for writing efficient and effective rules

Example prompts

  • "Create a YARA rule to detect the presence of a known ransomware signature in a file."
  • "Explain how to write a YARA rule that matches both hexadecimal and ASCII patterns."
  • "Generate a YARA rule with metadata fields for author, description, and reference links."

Tips & gotchas

  • Ensure you have a clear understanding of the target malware or pattern before writing rules to avoid false positives.
  • Use this skill in conjunction with actual samples or threat intelligence data for more accurate results.