Active Probing & Surface
low Severity
Free Check

Subdomain Exposure & Enumeration

Discovers active subdomains via Certificate Transparency logs and DNS resolution to map your external attack surface.

Test Your Website for Subdomain Exposure & Enumeration

Run this check along with 90+ automated tests across your domain.

Why It Matters

Unmonitored development, test, and staging subdomains often run outdated software without proper firewall defenses.

How We Check This

We aggregate domain records from Certificate Transparency logs, crt.sh, and common hostname lookups.

How to Fix & Implement

Copy-paste configuration blocks tailored for your web server or edge proxy.

nginx snippet
# Decommission or place unused subdomains behind an authentication proxy

Frequently Asked Questions

How do scanners find subdomains without brute force?

Every time an SSL certificate is generated, the domain is recorded publicly in Certificate Transparency logs.