MMC

Adversaries may abuse mmc.exe to proxy execution of malicious .msc files. Microsoft Management Console (MMC) is a binary that may be signed by Microsoft and is used in several ways in either its GUI or in a command prompt.(Citation: win_mmc)(Citation: what_is_mmc) MMC can be used to create, open, and save custom consoles that contain administrative tools created by Microsoft, called snap-ins. These snap-ins may be used to manage Windows systems locally or remotely. MMC can also be used to open Microsoft created .msc files to manage system configuration.(Citation: win_msc_files_overview)

For example, <code>mmc C:\Users\foo\admintools.msc /a</code> will open a custom, saved console msc file in author mode.(Citation: win_mmc) Another common example is <code>mmc gpedit.msc</code>, which will open the Group Policy Editor application window. 

Adversaries may use MMC commands to perform malicious tasks. For example, <code>mmc wbadmin.msc delete catalog -quiet</code> deletes the backup catalog on the system (i.e. [Inhibit System Recovery](https://attack.mitre.org/techniques/T1490)) without prompts to the user (Note: <code>wbadmin.msc</code> may only be present by default on Windows Server operating systems).(Citation: win_wbadmin_delete_catalog)(Citation: phobos_virustotal)

Adversaries may also abuse MMC to execute malicious .msc files. For example, adversaries may first create a malicious registry Class Identifier (CLSID) subkey, which uniquely identifies a [Component Object Model](https://attack.mitre.org/techniques/T1559/001) class object.(Citation: win_clsid_key) Then, adversaries may create custom consoles with the “Link to Web Address” snap-in that is linked to the malicious CLSID subkey.(Citation: mmc_vulns) Once the .msc file is saved, adversaries may invoke the malicious CLSID payload with the following command: <code>mmc.exe -Embedding C:\path\to\test.msc</code>.(Citation: abusing_com_reg)

Platforms: Windows
Tactics:
phase_name: defense-evasion

Detection:
Monitor processes and command-line parameters for suspicious or malicious use of MMC. Since MMC is a signed Windows binary, verify use of MMC is legitimate and not malicious. 

Monitor for creation and use of .msc files. MMC may legitimately be used to call Microsoft-created .msc files, such as <code>services.msc</code> or <code>eventvwr.msc</code>. Invoking non-Microsoft .msc files may be an indicator of malicious activity. 

References:
source_name: mitre-attack
description: bohops. (2018, August 18). ABUSING THE COM REGISTRY STRUCTURE (PART 2): HIJACKING & LOADING TECHNIQUES. Retrieved September 20, 2021.
source_name: abusing_com_reg
description: Boxiner, A., Vaknin, E. (2019, June 11). Microsoft Management Console (MMC) Vulnerabilities. Retrieved September 24, 2021.
source_name: mmc_vulns
description: Brinkmann, M.. (2017, June 10). Windows .msc files overview. Retrieved September 20, 2021.
source_name: win_msc_files_overview
description: Microsoft. (2017, October 16). mmc. Retrieved September 20, 2021.
source_name: win_mmc
description: Microsoft. (2017, October 16). wbadmin delete catalog. Retrieved September 20, 2021.
source_name: win_wbadmin_delete_catalog
description: Microsoft. (2018, May 31). CLSID Key. Retrieved September 24, 2021.
source_name: win_clsid_key
description: Microsoft. (2020, September 27). What is Microsoft Management Console?. Retrieved October 5, 2021.
source_name: what_is_mmc
description: Phobos Ransomware. (2020, December 30). Phobos Ransomware, Fast.exe. Retrieved September 20, 2021.
source_name: phobos_virustotal