hunt-subdomain

90 / 100 · Low risk

Fine to try. Some of what it can do is expected: a security skill usually runs scanners and checks websites.

By elementalsouls/Claude-BugHunter (GitHub) · security · 5,515 stars · scanned at commit d5dcc53

Hunting skill for subdomain takeover vulnerabilities. Includes modern provider fingerprints — Microsoft Azure DevOps `cloudapp.azure.com` regional-pool re-issue (1-click OAuth ATO via wildcard `reply_to`, Binary Security), Zendesk help-desk takeover → email interception → password reset chain (0xprial writeup), Vercel `cname.vercel-dns.com` deleted-project takeover, plus general Fastly CDN service re-attach and S3 dangling-bucket cookie-scope techniques. Use when hunting subdomain takeover — em…

Works with any agent that supports SKILL.md skills.

What this skill can do

Runs commands on your computer

The author does not mention this. Expected for a security skill.

Found in 10 places.

skills/hunt-subdomain/SKILL.md, line 65cat subdomains.txt | dnsx -a -cname -o resolved.txt
skills/hunt-subdomain/SKILL.md, line 70subjack -w subdomains.txt -t 100 -timeout 30 -ssl -c fingerprints.json
skills/hunt-subdomain/SKILL.md, line 107while read sub; do

Show 7 more

skills/hunt-subdomain/SKILL.md, line 120nuclei -l subdomains.txt -t ~/nuclei-templates/http/takeovers/ -severity medium,high,critical
skills/hunt-subdomain/SKILL.md, line 125subjack -w subdomains.txt -t 100 -timeout 30 -ssl -c $GOPATH/src/github.com/haccer/subjack/fingerprints.json -v
skills/hunt-subdomain/SKILL.md, line 130curl -sk "https://$subdomain" | grep -iE \
skills/hunt-subdomain/SKILL.md, line 136curl -Isk "https://target.com" | grep -i "set-cookie" | grep "domain=.target.com"
skills/hunt-subdomain/SKILL.md, line 141curl -sI "https://subdomain.target.com" -H "Host: subdomain.target.com" | grep -i "fastly\|x-served-by\|x-cache"
skills/hunt-subdomain/SKILL.md, line 147aws s3api head-bucket --bucket <extracted-bucket-name> 2>&1 | grep -i "NoSuchBucket\|403\|404"
skills/hunt-subdomain/SKILL.md, line 152dig CNAME sub.target.com

Sends data to these websites: subdomain.target.com, $subdomain, target.com, api.target.com

The author does not mention this. Expected for a security skill.

Found in 7 places.

skills/hunt-subdomain/SKILL.md, line 77- `curl -sk https://subdomain.target.com` — check for provider error string
skills/hunt-subdomain/SKILL.md, line 130curl -sk "https://$subdomain" | grep -iE \
skills/hunt-subdomain/SKILL.md, line 136curl -Isk "https://target.com" | grep -i "set-cookie" | grep "domain=.target.com"

Show 4 more

skills/hunt-subdomain/SKILL.md, line 141curl -sI "https://subdomain.target.com" -H "Host: subdomain.target.com" | grep -i "fastly\|x-served-by\|x-cache"
skills/hunt-subdomain/SKILL.md, line 142curl -sk "https://subdomain.target.com" | grep -i "fastly error"
skills/hunt-subdomain/SKILL.md, line 212- `curl -sk https://subdomain.target.com` → confirms provider error string
skills/hunt-subdomain/SKILL.md, line 295- **C.** Attacker page hosted on the taken-over subdomain issues `fetch('https://api.target.com/account', {credentials:'include'})`. CORS preflight passes. Serv

Install

Paste this into your terminal. It downloads exactly the version we scanned, not whatever is newest.

if [ -e ~/.agents/skills/'hunt-subdomain' ] || [ -L ~/.agents/skills/'hunt-subdomain' ]; then echo 'A skill folder named hunt-subdomain already exists — not replacing it' >&2; false; else d=$(mktemp -d) && git clone --quiet --filter=blob:none --no-checkout 'https://github.com/elementalsouls/Claude-BugHunter' "$d" && git -C "$d" checkout --quiet 'd5dcc5347675ed431488e0a0e46749e4918aa194' -- 'skills/hunt-subdomain' && mkdir -p ~/.agents/skills && cp -R "$d"/'skills/hunt-subdomain' ~/.agents/skills/'hunt-subdomain' && rm -rf "$d"; fi

Codex reads ~/.agents/skills directly. For Claude Code, Cursor, Copilot, Gemini CLI, Antigravity or OpenCode, also link it. For Claude Code: ln -s ~/.agents/skills/'hunt-subdomain' ~/.claude/skills/'hunt-subdomain' (other agents: ~/.cursor/skills, ~/.copilot/skills, ~/.gemini/skills, ~/.gemini/config/skills, ~/.config/opencode/skills). Or install through the finder skill, which does both.

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Score history

Date	Version	Score
2026-11-10	`d5dcc53`	90
2026-11-08	`42a3ab1`	90
2026-11-06	`3e71af0`	90