Adversaries may search freely available technical databases for information about victims that can be used during targeting. Information about victims may be available in online databases and repositories, such as registrations of domains/certificates as well as public collections of network data/artifacts gathered from traffic and/or scans.(Citation: WHOIS)(Citation: DNS Dumpster)(Citation: Circl Passive DNS)(Citation: Medium SSL Cert)(Citation: SSLShopper Lookup)(Citation: DigitalShadows CDN)(Citation: Shodan)

Adversaries may search in different open databases depending on what information they seek to gather. Information from these sources may reveal opportunities for other forms of reconnaissance (ex: [Phishing for Information](https://attack.mitre.org/techniques/T1598) or [Search Open Websites/Domains](https://attack.mitre.org/techniques/T1593)), establishing operational resources (ex: [Acquire Infrastructure](https://attack.mitre.org/techniques/T1583) or [Compromise Infrastructure](https://attack.mitre.org/techniques/T1584)), and/or initial access (ex: [External Remote Services](https://attack.mitre.org/techniques/T1133) or [Trusted Relationship](https://attack.mitre.org/techniques/T1199)).
Search Open Technical Databases
source_name: mitre-attack  url: https://attack.mitre.org/techniques/T1596  external_id: T1596     source_name: Circl Passive DNS  description: CIRCL Computer Incident Response Center. (n.d.). Passive DNS. Retrieved October 20, 2020.  url: https://www.circl.lu/services/passive-dns/     source_name: DNS Dumpster  description: Hacker Target. (n.d.). DNS Dumpster. Retrieved October 20, 2020.  url: https://dnsdumpster.com/     source_name: Medium SSL Cert  description: Jain, M. (2019, September 16). Export & Download — SSL Certificate from Server (Site URL). Retrieved October 20, 2020.  url: https://medium.com/@menakajain/export-download-ssl-certificate-from-server-site-url-bcfc41ea46a2     source_name: WHOIS  description: NTT America. (n.d.). Whois Lookup. Retrieved October 20, 2020.  url: https://www.whois.net/     source_name: Shodan  description: Shodan. (n.d.). Shodan. Retrieved October 20, 2020.  url: https://shodan.io     source_name: SSLShopper Lookup  description: SSL Shopper. (n.d.). SSL Checker. Retrieved October 20, 2020.  url: https://www.sslshopper.com/ssl-checker.html     source_name: DigitalShadows CDN  description: Swisscom & Digital Shadows. (2017, September 6). Content Delivery Networks (CDNs) Can Leave You Exposed – How You Might Be Affected And What You Can Do About It. Retrieved October 20, 2020.  url: https://www.digitalshadows.com/blog-and-research/content-delivery-networks-cdns-can-leave-you-exposed-how-you-might-be-affected-and-what-you-can-do-about-it/     