T1592

Adversaries may gather this information in various ways, such as direct collection actions via Active Scanning or Phishing for Information.

Adversaries may also compromise sites then include malicious content designed to collect host information from visitors.(Citation: ATT ScanBox) Information about hosts may also be exposed to adversaries via online or other accessible data sets (ex: Social Media or Search Victim-Owned Websites).

Gathering this information may reveal opportunities for other forms of reconnaissance (ex: Search Open Websites/Domains or Search Open Technical Databases), establishing operational resources (ex: Develop Capabilities or Obtain Capabilities), and/or initial access (ex: Supply Chain Compromise or External Remote Services).

Adversaries may also gather victim host information via User-Agent HTTP headers, which are sent to a server to identify the application, operating system, vendor, and/or version of the requesting user agent. This can be used to inform the adversary’s follow-on action. For example, adversaries may check user agents for the requesting operating system, then only serve malware for target operating systems while ignoring others.(Citation: TrellixQakbot)