Certificate Transparency Subdomain & Host Finder
Audit and enumerate exposed subdomains and hostnames using cryptographic Certificate Transparency (CT) logs (RFC 6962). Discover mail gateways, staging environments, API servers, and CDN endpoints issued by public Certificate Authorities.
What is Certificate Transparency?
Certificate Transparency (CT) is an open cryptographic auditing framework governed by IETF RFC 6962. Major web browsers (Google Chrome, Apple Safari, Mozilla Firefox) require that every publicly trusted SSL/TLS certificate issued by a Certificate Authority (CA) be submitted to publicly auditable, append-only Merkle tree logs.
Because every certificate issuance is permanently registered before browsers accept the connection, CT logs provide an exhaustive historical map of every hostname created for an organization.
Security and Reconnaissance Uses
- Shadow IT Discovery: Uncover unmanaged dev, test, and staging environments exposed to the public Internet.
- Brand Defense: Track newly issued SSL certificates mimicking high-value domain names to intercept phishing sites before activation.
- DNS Hygiene: Identify orphaned subdomains pointing to deallocated cloud servers vulnerable to Subdomain Takeover (CNAME hijacking).
- API Surface Mapping: Audit legacy API endpoints and regional cloud gateways forgotten by previous engineering deployments.