Individual skill
subdomain-takeover
Subdomain takeover detection and exploitation playbook. Use when targets have dangling CNAME/NS/MX records pointing to deprovisioned cloud resources, expired third-party services, or unclaimed SaaS tenants that an attacker can register to serve content under the victim's domain.
knowledge/hack-skills/skills/subdomain-takeover/SKILL.md
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- Last checked
- Nov 10, 2026
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- Repository last updated
- Nov 5, 2026
- License
- Apache-2.0
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- ai-agent Repository topic
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SKILL.mdcore · 10,857 bytes
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# SKILL: Subdomain Takeover — Detection & Exploitation Playbook
> **AI LOAD INSTRUCTION**: Covers CNAME/NS/MX takeover, per-provider fingerprint matching, claim procedures, and defensive monitoring. Base models often confuse "CNAME exists" with "takeover possible" — the key is whether the *resource behind the CNAME is unclaimed and claimable*.
## 0. RELATED ROUTING
- [ssrf-server-side-request-forgery](../ssrf-server-side-request-forgery/SKILL.md) when a subdomain takeover is used to bypass SSRF allowlists trusting `*.target.com`
- [cors-cross-origin-misconfiguration](../cors-cross-origin-misconfiguration/SKILL.md) when CORS trusts `*.target.com` — takeover → full cross-origin read
- [xss-cross-site-scripting](../xss-cross-site-scripting/SKILL.md) takeover gives you script execution under target origin (cookie theft, OAuth redirect abuse)
- [http-host-header-attacks](../http-host-header-attacks/SKILL.md) when Host routing leads to subdomain-scoped cache or auth issues
- [web-cache-deception](../web-cache-deception/SKILL.md) when a taken-over subdomain shares cache with the main domain
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