Adversaries may target user email to collect sensitive information. Emails may contain sensitive data, including trade secrets or personal information, that can prove valuable to adversaries. Adversaries can collect or forward email from mail servers or clients. 
Email Collection
source_name: mitre-attack  url: https://attack.mitre.org/techniques/T1114  external_id: T1114     source_name: Microsoft Tim McMichael Exchange Mail Forwarding 2  description: McMichael, T.. (2015, June 8). Exchange and Office 365 Mail Forwarding. Retrieved October 8, 2019.  url: https://blogs.technet.microsoft.com/timmcmic/2015/06/08/exchange-and-office-365-mail-forwarding-2/     