Sub-technique of T1137 Office Application Startup.View on attack.mitre.org
Adversaries may abuse Microsoft Office templates to obtain persistence on a compromised system. Microsoft Office contains templates that are part of common Office applications and are used to customize styles. The base templates within the application are used each time an application starts.
Office Visual Basic for Applications (VBA) macros can be inserted into the base template and used to execute code when the respective Office application starts in order to obtain persistence. Examples for both Word and Excel have been discovered and published. By default, Word has a Normal.dotm template created that can be modified to include a malicious macro. Excel does not have a template file created by default, but one can be added that will automatically be loaded. Shared templates may also be stored and pulled from remote locations.
Word Normal.dotm location:<br>C:\Users\<username>\AppData\Roaming\Microsoft\Templates\Normal.dotm
Excel Personal.xlsb location:<br>C:\Users\<username>\AppData\Roaming\Microsoft\Excel\XLSTART\PERSONAL.XLSB
Adversaries may also change the location of the base template to point to their own by hijacking the application's search order, e.g. Word 2016 will first look for Normal.dotm under C:\Program Files (x86)\Microsoft Office\root\Office16\, or by modifying the GlobalDotName registry key. By modifying the GlobalDotName registry key an adversary can specify an arbitrary location, file name, and file extension to use for the template that will be loaded on application startup. To abuse GlobalDotName, adversaries may first need to register the template as a trusted document or place it in a trusted location.
An adversary may need to enable macros to execute unrestricted depending on the system or enterprise security policy on use of macros.
Rules on DetectionCode tagged with T1137.001.
| Used by | Procedure example |
|---|---|
| GroupMuddyWater | MuddyWater has used a Word Template, Normal.dotm, for persistence. |
| Used by | Procedure example |
|---|---|
| MalwareBackConfig | BackConfig has the ability to use hidden columns in Excel spreadsheets to store executable files or commands for VBA macros. |
| MalwareCobalt Strike | Cobalt Strike has the ability to use an Excel Workbook to execute additional code by enabling Office to trust macros and execute code without user permission. |
| MalwareROAMINGHOUSE | ROAMINGHOUSE has been loaded as a Word Template file when victims opened a decoy document placed in `%APPDATA%\Microsoft\Templates` alongside a ROAMINGHOUSE macro. |
| Used by | Procedure example |
|---|---|
| CampaignOperation AkaiRyū | During Operation AkaiRyū, MirrorFace loaded malicious Word templates containing VBA code leading to installation of UPPERCUT. |
Data from MITRE ATT&CK® (Enterprise). ATT&CK® is a registered trademark of The MITRE Corporation.
