Subfinder Passive Subdomain Enumeration

Quality score: 70/100 · Category: Security · Sub-category: red-team

Subfinder is a passive subdomain discovery tool by ProjectDiscovery that finds valid subdomains for websites using curated online sources. Optimized for speed and stealth, it integrates cleanly into security reconnaissance pipelines via stdin/stdout support.

What this skill does

Subfinder Passive Subdomain Enumeration is a production-ready Claude Code skill (quality score 70/100) in the red-team sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/subfinder-passive-subdomain-enumeration/ and loads when your prompt matches the skill's trigger.

Who uses this skill

The Subfinder Passive Subdomain Enumeration skill is built for security engineers, penetration testers, DevSecOps practitioners, and development teams hardening codebases and infrastructure. It is part of the open ClaudSkills registry, a community-curated catalog of 15,000+ capabilities you can install for Claude Code — the Claude CLI agent.

How to install

Free

Manual install (2 steps)

mkdir -p ~/.claude/skills/subfinder-passive-subdomain-enumeration
curl -L https://claudskills.com/skills/subfinder-passive-subdomain-enumeration/SKILL.md \
  -o ~/.claude/skills/subfinder-passive-subdomain-enumeration/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/subfinder-passive-subdomain-enumeration/. Claude Code auto-discovers it on next session.

Skills live at ~/.claude/skills/subfinder-passive-subdomain-enumeration/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\subfinder-passive-subdomain-enumeration\SKILL.md on Windows. See the full install guide for step-by-step instructions.

Pro

One-click install via the desktop app

The ClaudSkills desktop app installs any skill directly into ~/.claude/skills/ with one click — no terminal required. Pro starts at $9/mo or $149 lifetime.

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Part of ClaudSkills — the open registry for Claude Code skills. · What's New · Install guide · About · llms.txt

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