# Subdomain Takeover Risk

> Detects CNAME records pointing to cloud services that may be dangling, and configurations referencing external services vulnerable to takeover.

- Skill: `zakirkun/subdomain-takeover-risk` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add zakirkun/subdomain-takeover-risk`
- Raw SKILL.md: https://api.skillmd.com/api/skills/zakirkun/subdomain-takeover-risk/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: DevOps & Infra
- Author: zakirkun (https://skillmd.com/u/zakirkun)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/zakirkun/subdomain-takeover-risk

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# Subdomain Takeover Risk

## Overview
Subdomain takeover occurs when a DNS CNAME points to a third-party service (GitHub Pages, Heroku, S3, Netlify) whose content has been removed. An attacker can claim the now-unclaimed resource on the third-party platform and host malicious content that browsers serve under the original company's subdomain.

## Remediation
- Regularly audit DNS records and remove CNAMEs for deprovisioned services
- Before deprovisioning cloud resources, remove DNS records first
- Monitor subdomain availability with tools like `can-i-take-over-xyz`