T1218.014 MMC

> Sub-technique of: T1218

High-Level Description

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. 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.

For example, <code>mmc C:\Users\foo\admintools.msc /a</code> will open a custom, saved console msc file in author mode. 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) without prompts to the user (Note: <code>wbadmin.msc</code> may only be present by default on Windows Server operating systems).

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 class object. Then, adversaries may create custom consoles with the “Link to Web Address” snap-in that is linked to the malicious CLSID subkey. 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>.

Kill Chain Phase

• Defense Evasion (TA0005)

Platforms: Windows

What to Check

• ] Identify if MMC technique is applicable to target environment
• ] Check Windows systems for indicators of MMC
• ] Verify mitigations are bypassed or absent (2 known mitigations)
• ] Assess detection coverage (1 detection strategies)

How to Test

Manual Testing

1. Identify Attack Surface: Determine if the target environment is susceptible to MMC by examining the target platforms (Windows).

1. Assess Existing Defenses: Review whether mitigations for T1218.014 are in place. If defenses are absent or misconfigured, this technique may be exploitable.

1. Execute Test: Use tools and methods described in the MITRE ATT&CK page and external references below.

> Note: No Atomic Red Team tests available for this technique. See Atomic Red Team GitHub for updates.

Remediation Guide

M1042 Disable or Remove Feature or Program

MMC may not be necessary within a given environment since it is primarily used by system administrators, not regular users or clients.

M1038 Execution Prevention

Use application control configured to block execution of MMC if it is not required for a given system or network to prevent potential misuse by adversaries.

Detection

Detecting MMC (.msc) Proxy Execution and Malicious COM Activation

Risk Assessment

| Finding | Severity | Impact | | ------------------------ | -------- | --------------- | | MMC technique applicable | Medium | Defense Evasion |

CWE Categories

| CWE ID | Title | | ------- | ---------------------------- | | CWE-693 | Protection Mechanism Failure |

References

• abusing_com_reg
• mmc_vulns
• win_msc_files_overview
• win_mmc
• win_wbadmin_delete_catalog
• win_clsid_key
• what_is_mmc
• phobos_virustotal
• Atomic Red Team - T1218.014
• MITRE ATT&CK - T1218.014