Organisations accumulate subdomains over time — dev., staging., old., admin., vpn. Each one is a potential door, and forgotten ones are rarely patched or monitored.
Why they are risky
- Stale software. A neglected staging box may run outdated, vulnerable code.
- Subdomain takeover. A subdomain pointing at a deprovisioned cloud service can sometimes be claimed by an attacker.
- Information leakage. Dev environments often expose debug pages, configs or test data.
What to do
Inventory your subdomains regularly, retire what you no longer use, and remove DNS records for decommissioned services. The web scan enumerates discoverable subdomains so you can see your external footprint.