subdomain-takeover-check git:20260504.2a64374A

Immutable. This exact content is served forever at /api/v1/blob/5c25b30590c677c3.

---
name: subdomain-takeover-check
description: Ground-truth subdomain takeover candidates against can-i-take-over-xyz before reporting. Use when an agent or scanner flags a potential subdomain takeover, dangling CNAME, or unclaimed cloud resource.
---

# Subdomain Takeover Ground-Truth Check

Validates subdomain takeover candidates against the canonical [can-i-take-over-xyz](https://github.com/EdOverflow/can-i-take-over-xyz) service registry.

## Procedure

1. **Resolve DNS** — `dig CNAME <subdomain>` to identify the target service
2. **Fetch the registry** — pull the raw README from `https://raw.githubusercontent.com/EdOverflow/can-i-take-over-xyz/master/README.md` and find the service row
3. **Check status** — is the service listed as `Vulnerable`, `Not Vulnerable`, or `Edge Case`?
4. **Match fingerprint** — does the HTTP response body match the documented fingerprint? (e.g. `NoSuchBucket`, `There isn't a GitHub Pages site here`)
5. **Credence check** — run `credence assess_confidence` with: service name, registry status, fingerprint match result, and raw evidence

## Output

Always log the result in the target's gadget-ledger and flag to the user. Format:

```
## Subdomain Takeover: <subdomain>
- CNAME: <target>
- Service: <service name>
- Registry status: Vulnerable | Not Vulnerable | Edge Case | Not Listed
- Fingerprint match: Yes | No | N/A
- Credence: <confidence level>
- Verdict: LIKELY VALID | INVESTIGATE | LIKELY FP
```

## Philosophy

**Prefer alerts over missed true positives.** This check adds confidence, not a gate. If the service is Not Listed or the fingerprint is ambiguous, flag it as INVESTIGATE — never silently drop.