subfinder

Subfinder is a fast passive subdomain enumeration tool designed to discover valid subdomains for websites by leveraging curated online sources. Its primary use case is for penetration testers and bug bounty hunters who require stealthy and efficient subdomain discovery, featuring modules for resolution and wildcard elimination, multiple output formats, and resource optimization. Subfinder supports STDIN/OUT integration and offers customizable source selection, filtering options, and rate-limiting to enhance its performance and adaptability in various workflows.