ctf-osint

84 / 100 · Low risk

Fine to try. Some of what it can do is expected: a coding skill usually runs build and test commands.

By ljagiello/ctf-skills (GitHub) · coding · 3,679 stars · scanned at commit e79be29

Provides open source intelligence techniques for CTF challenges. Use when gathering information from public sources, social media, geolocation, DNS records, username enumeration, reverse image search, Google dorking, Wayback Machine, Tor relays, FEC filings, or identifying unknown data like hashes and coordinates.

Works with any agent that supports SKILL.md skills.

What this skill can do

Downloads and installs other software

This is disclosed by the author in the skill's SKILL.md or README.

Found in 5 places.

ctf-osint/SKILL.md, line 20pip install shodan Pillow
ctf-osint/SKILL.md, line 25apt install whois dnsutils nmap libimage-exiftool-perl imagemagick curl
ctf-osint/SKILL.md, line 30brew install whois bind nmap exiftool imagemagick curl

Show 2 more

ctf-osint/tools-mcp.md, line 26npx @playwright/mcp@latest # most MCP clients auto-launch this
ctf-osint/tools-mcp.md, line 29npx @playwright/mcp@latest install-browser chrome-for-testing

Runs commands on your computer

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

Found in 7 places.

ctf-osint/SKILL.md, line 20pip install shodan Pillow
ctf-osint/SKILL.md, line 25apt install whois dnsutils nmap libimage-exiftool-perl imagemagick curl
ctf-osint/SKILL.md, line 30brew install whois bind nmap exiftool imagemagick curl

Show 4 more

ctf-osint/SKILL.md, line 54dig +short -t txt target.com
ctf-osint/SKILL.md, line 122exiftool image.jpg # EXIF data
ctf-osint/SKILL.md, line 143dig -t txt subdomain.ctf.domain.com
ctf-osint/SKILL.md, line 168curl "http://ip-api.com/json/103.150.68.150"

Sends data to these websites: web.archive.org, ip-api.com, ipinfo.io, username.tumblr.com, public.api.bsky.app, discord.com, api.securitytrails.com, reverse-whois-api.whoisxmlapi.com

This is disclosed by the author in the skill's SKILL.md or README.

Found in 21 places.

ctf-osint/SKILL.md, line 66curl "https://web.archive.org/web/20230101*/target.com"
ctf-osint/SKILL.md, line 91- Blog check: `curl -sI` for `x-tumblr-user` header. Avatar at `/avatar/512`. See [social-media.md](social-media.md).
ctf-osint/SKILL.md, line 168curl "http://ip-api.com/json/103.150.68.150"

Show 17 more

ctf-osint/geolocation-and-media.md, line 221curl "http://ip-api.com/json/103.150.68.150"
ctf-osint/geolocation-and-media.md, line 224curl "https://ipinfo.io/103.150.68.150/json"
ctf-osint/social-media.md, line 42curl "http://web.archive.org/cdx/search/cdx?url=twitter.com/USERNAME*&output=json&fl=timestamp,original,statuscode"
ctf-osint/social-media.md, line 45curl "http://web.archive.org/cdx/search/cdx?url=pbs.twimg.com/profile_images/*&output=json"
ctf-osint/social-media.md, line 48curl "http://web.archive.org/cdx/search/cdx?url=t.co/SHORTCODE&output=json"
ctf-osint/social-media.md, line 54- `curl -sI "https://USERNAME.tumblr.com"` -> look for `x-tumblr-user` header (confirms blog exists even if API returns 401)
ctf-osint/social-media.md, line 212curl -s "https://public.api.bsky.app/xrpc/app.bsky.feed.searchPosts?q=metactf+flash+ctf&sort=latest" | jq '.posts[].record.text'
ctf-osint/social-media.md, line 215curl -s "https://public.api.bsky.app/xrpc/app.bsky.actor.searchActors?q=metactf" | jq '.actors[].handle'
ctf-osint/social-media.md, line 218curl -s "https://public.api.bsky.app/xrpc/app.bsky.actor.getProfile?actor=metactf.bsky.social" | jq
ctf-osint/social-media.md, line 221curl -s "https://public.api.bsky.app/xrpc/app.bsky.feed.getAuthorFeed?actor=metactf.bsky.social&limit=50" | jq '.feed[].post.record.text'
ctf-osint/social-media.md, line 224curl -s "https://public.api.bsky.app/xrpc/app.bsky.feed.getPostThread?uri=at://did:plc:.../app.bsky.feed.post/..." | jq
ctf-osint/social-media.md, line 304curl -H "Authorization: $TOKEN" "https://discord.com/api/v10/guilds/GUILD_ID/roles"
ctf-osint/social-media.md, line 306curl -H "Authorization: $TOKEN" "https://discord.com/api/v10/guilds/GUILD_ID/emojis"
ctf-osint/social-media.md, line 308curl -H "Authorization: $TOKEN" "https://discord.com/api/v10/guilds/GUILD_ID/messages/search?content=flag"
ctf-osint/web-and-dns.md, line 154curl "http://web.archive.org/cdx/search/cdx?url=example.com*&output=json&fl=timestamp,original,statuscode"
ctf-osint/web-and-dns.md, line 174curl "https://api.securitytrails.com/v1/domain/example.com/whois" \
ctf-osint/web-and-dns.md, line 179curl "https://reverse-whois-api.whoisxmlapi.com/api/v2" \

and 1 more places

Install

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

if [ -e ~/.agents/skills/'ctf-osint' ] || [ -L ~/.agents/skills/'ctf-osint' ]; then echo 'A skill folder named ctf-osint already exists — not replacing it' >&2; false; else d=$(mktemp -d) && git clone --quiet --filter=blob:none --no-checkout 'https://github.com/ljagiello/ctf-skills' "$d" && git -C "$d" checkout --quiet 'e79be2925d1612e8a97070d6201e300286672370' -- 'ctf-osint' && mkdir -p ~/.agents/skills && cp -R "$d"/'ctf-osint' ~/.agents/skills/'ctf-osint' && 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/'ctf-osint' ~/.claude/skills/'ctf-osint' (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
2026-11-11	`e79be29`	84
2026-11-08	`2ad85d3`	84
2026-11-07	`2ad85d3`	54