Subissues
| Bezeichnung | Beschreibung |
|---|---|
| Local Email Collection | Adversaries may target user email on local systems to collect sensitive information. Files containing email data can be acquired from a user’s local system, such as Outlook storage or cache files.
Outlook stores data locally in offline data files with an extension of .ost. Outlook 2010 and later supports .ost file sizes up to 50GB, while earlier versions of Outlook support up to 20GB.(Citation: Outlook File Sizes) IMAP accounts in Outlook 2013 (and earlier) and POP accounts use Outlook Data Files (.pst) as opposed to .ost, whereas IMAP accounts in Outlook 2016 (and later) use .ost files. Both types of Outlook data files are typically stored in `C:\Users\ |
| Email Forwarding Rule | Adversaries may setup email forwarding rules to collect sensitive information. Adversaries may abuse email forwarding rules to monitor the activities of a victim, steal information, and further gain intelligence on the victim or the victim’s organization to use as part of further exploits or operations.(Citation: US-CERT TA18-068A 2018) Furthermore, email forwarding rules can allow adversaries to maintain persistent access to victim's emails even after compromised credentials are reset by administrators.(Citation: Pfammatter - Hidden Inbox Rules) Most email clients allow users to create inbox rules for various email functions, including forwarding to a different recipient. These rules may be created through a local email application, a web interface, or by command-line interface. Messages can be forwarded to internal or external recipients, and there are no restrictions limiting the extent of this rule. Administrators may also create forwarding rules for user accounts with the same considerations and outcomes.(Citation: Microsoft Tim McMichael Exchange Mail Forwarding 2)(Citation: Mac Forwarding Rules) Any user or administrator within the organization (or adversary with valid credentials) can create rules to automatically forward all received messages to another recipient, forward emails to different locations based on the sender, and more. Adversaries may also hide the rule by making use of the Microsoft Messaging API (MAPI) to modify the rule properties, making it hidden and not visible from Outlook, OWA or most Exchange Administration tools.(Citation: Pfammatter - Hidden Inbox Rules) In some environments, administrators may be able to enable email forwarding rules that operate organization-wide rather than on individual inboxes. For example, Microsoft Exchange supports transport rules that evaluate all mail an organization receives against user-specified conditions, then performs a user-specified action on mail that adheres to those conditions.(Citation: Microsoft Mail Flow Rules 2023) Adversaries that abuse such features may be able to enable forwarding on all or specific mail an organization receives. |
| Remote Email Collection | Adversaries may target an Exchange server, Office 365, or Google Workspace to collect sensitive information. Adversaries may leverage a user's credentials and interact directly with the Exchange server to acquire information from within a network. Adversaries may also access externally facing Exchange services, Office 365, or Google Workspace to access email using credentials or access tokens. Tools such as [MailSniper](https://attack.mitre.org/software/S0413) can be used to automate searches for specific keywords. |
Linked Issues
- MITREATTACK -
© 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. https://attack.mitre.org/
Terms of Use
LICENSE
The MITRE Corporation (MITRE) hereby grants you a non-exclusive, royalty-free license to use ATT&CK® for research, development, and commercial purposes. Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.
"© 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation."
DISCLAIMERS
MITRE does not claim ATT&CK enumerates all possibilities for the types of actions and behaviors documented as part of its adversary model and framework of techniques. Using the information contained within ATT&CK to address or cover full categories of techniques will not guarantee full defensive coverage as there may be undisclosed techniques or variations on existing techniques not documented by ATT&CK.
ALL DOCUMENTS AND THE INFORMATION CONTAINED THEREIN ARE PROVIDED ON AN "AS IS" BASIS AND THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE MITRE CORPORATION, ITS BOARD OF TRUSTEES, OFFICERS, AGENTS, AND EMPLOYEES, DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION THEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
See our FAQ for more information on how to use and represent the ATT&CK name.