Sublist3r is a powerful, open-source Python tool designed for subdomain enumeration using Open-Source Intelligence (OSINT). Integrated into Kali Linux, it assists ethical hackers, penetration testers, and bug bounty hunters in discovering subdomains associated with a target domain. By leveraging search engines like Bing, Yahoo, Google, Baidu, and Ask, as well as services such as Netcraft, VirusTotal, ThreatCrowd, DNSdumpster, and ReverseDNS, Sublist3r compiles comprehensive subdomain lists. It also integrates Subbrute for brute-force enumeration, enhancing its ability to uncover hidden subdomains.