CyberStack

MITRE ATT&CK / Techniques / T1021.003

Remote Services: Distributed Component Object Model

ID
T1021.003
Tactics
TA0008 Lateral Movement
Sub-technique of
T1021 Remote Services
Platforms
Windows
Data sources
Logon Session Creation, Network Connection Creation, Process Creation, Module Load
Source
attack.mitre.org
MITRE last modified
25 Oct 2025

Adversaries may use Valid Accounts to interact with remote machines by taking advantage of Distributed Component Object Model (DCOM). The adversary may then perform actions as the logged-on user.

The Windows Component Object Model (COM) is a component of the native Windows application programming interface (API) that enables interaction between software objects, or executable code that implements one or more interfaces. Through COM, a client object can call methods of server objects, which are typically Dynamic Link Libraries (DLL) or executables (EXE). Distributed COM (DCOM) is transparent middleware that extends the functionality of COM beyond a local computer using remote procedure call (RPC) technology.[6][7]

Permissions to interact with local and remote server COM objects are specified by access control lists (ACL) in the Registry.[1] By default, only Administrators may remotely activate and launch COM objects through DCOM.[3]

Through DCOM, adversaries operating in the context of an appropriately privileged user can remotely obtain arbitrary and even direct shellcode execution through Office applications[8] as well as other Windows objects that contain insecure methods.[9][10] DCOM can also execute macros in existing documents[11] and may also invoke Dynamic Data Exchange (DDE) execution directly through a COM created instance of a Microsoft Office application[12], bypassing the need for a malicious document. DCOM can be used as a method of remotely interacting with Windows Management Instrumentation. [13]

Detection

Mitigations (4)

M1026 Privileged Account Management

Modify Registry settings (directly or using Dcomcnfg.exe) in HKEY_LOCAL_MACHINE\SOFTWARE\Classes\AppID\{{AppID_GUID}} associated with the process-wide security of individual COM applications.[1]

Modify Registry settings (directly or using Dcomcnfg.exe) in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Ole associated with system-wide security defaults for all COM applications that do not set their own process-wide security.[2] [3]

M1030 Network Segmentation

Enable Windows firewall, which prevents DCOM instantiation by default.

M1042 Disable or Remove Feature or Program

Consider disabling DCOM through Dcomcnfg.exe.[4]

M1048 Application Isolation and Sandboxing

Ensure all COM alerts and Protected View are enabled.[5]

Software (3)

References

  1. Microsoft Process Wide Com Keys
  2. Microsoft System Wide Com Keys
  3. Microsoft COM ACL
  4. Microsoft Disable DCOM
  5. Microsoft Protected View
  6. Fireeye Hunting COM June 2019
  7. Microsoft COM
  8. Enigma Outlook DCOM Lateral Movement Nov 2017
  9. Enigma MMC20 COM Jan 2017
  10. Enigma DCOM Lateral Movement Jan 2017
  11. Enigma Excel DCOM Sept 2017
  12. Cyberreason DCOM DDE Lateral Movement Nov 2017
  13. MSDN WMI