T1589.002 Email Addresses
Adversaries may gather email addresses that can be used during targeting. Even if internal instances exist, organizations may have public-facing email infrastructure and addresses for employees.
Adversaries may easily gather email addresses, since they may be readily available and exposed via online or other accessible data sets (ex: Social Media or Search Victim-Owned Websites). Email addresses could also be enumerated via more active means (i.e. Active Scanning), such as probing and analyzing responses from authentication services that may reveal valid usernames in a system.
Gathering this information may reveal opportunities for other forms of reconnaissance (ex: Search Open Websites/Domains or Phishing for Information), establishing operational resources (ex: Email Accounts), and/or initial access (ex: Phishing or Brute Force via External Remote Services).
||AADInternals can check for the existence of user email addresses using public Microsoft APIs.
||APT32 has collected e-mail addresses for activists and bloggers in order to target them with spyware.
||HAFNIUM has collected e-mail addresses for users they intended to target.
||Kimsuky has collected valid email addresses that were subsequently used in spearphishing campaigns.
||Lazarus Group collected email addresses belonging to various departments of a targeted organization which were used in follow-on phishing campaigns.
||Magic Hound has acquired the personal email addresses of some individuals they intend to target.
||MuddyWater has specifically targeted government agency employees with spearphishing e-mails.
||Sandworm Team has obtained valid emails addresses while conducting research against target organizations that were subsequently used in spearphishing campaigns.
||Silent Librarian has collected e-mail addresses from targeted organizations from open Internet searches.
||TA551 has used spoofed company emails that were acquired from email clients on previously infected hosts to target other individuals.
||This technique cannot be easily mitigated with preventive controls since it is based on behaviors performed outside of the scope of enterprise defenses and controls. Efforts should focus on minimizing the amount and sensitivity of data available to external parties.