The OWASP Amass Project performs network mapping of attack surfaces and external asset discovery using open source information gathering and active reconnaissance techniques. Information Gathering Techniques Used: Technique Data Sources APIs 360PassiveDNS, Ahrefs, AnubisDB, BeVigil, BinaryEdge, BufferOver, BuiltWith, C99, Chaos, CIRCL, DNSDB, DNSRepo, Deepinfo, Detectify, FOFA, FullHunt, GitHub, GitLab, GrepApp, Greynoise, HackerTarget, Hunter, IntelX, LeakIX, Maltiverse, Mnemonic, Netlas, Pastebin, PassiveTotal, PentestTools, Pulsedive, Quake, SOCRadar, Searchcode, Shodan, Spamhaus, Sublist3rAPI, SubdomainCenter, ThreatBook, ThreatMiner, URLScan, VirusTotal, Yandex, ZETAlytics, ZoomEye Certificates Active pulls (optional), Censys, CertCentral, CertSpotter, Crtsh, Digitorus, FacebookCT DNS Brute forcing, Reverse DNS sweeping, NSEC zone walking, Zone transfers, FQDN alterations/permutations, FQDN Similarity-based Guessing Routing ASNLookup, BGPTools, BGPView, BigDataCloud, IPdata, IPinfo, RADb, Robtex, ShadowServer, TeamCymru Scraping AbuseIPDB, Ask, Baidu, Bing, CSP Header, DNSDumpster, DNSHistory, DNSSpy, DuckDuckGo, Gists, Google, HackerOne, HyperStat, PKey, RapidDNS