T1175

Component Object Model and Distributed COM

Adversaries may abuse the Windows Component Object Model (COM) and Distributed Component Object Model (DCOM) for local code execution or to move laterally across a network. This deprecated technique encompasses both local COM abuse (now T1559.001) and DCOM-based lateral movement (now T1021.003). COM is a native Windows API component enabling interaction between software objects through well-defined interfaces; DCOM extends this functionality over a network via RPC. Adversaries exploit COM interfaces to invoke arbitrary code execution through C++, Java, VBScript, and PowerShell. For DCOM lateral movement, privileged users can remotely activate objects such as MMC20.Application (CLSID: 49B2791A-B1AE-4C90-9B8E-E860BA07F889), ShellWindows (CLSID: 9BA05972-F6A8-11CF-A442-00A0C90A8F39), and ShellBrowserWindow (CLSID: C08AFD90-F2A1-11D1-8455-00A0C91F3880) to execute commands on remote hosts. Microsoft Office application objects (Excel.Application, Outlook.Application) exposed via DCOM also permit remote code execution and macro invocation. COM surrogate processes (dllhost.exe /Processid:{CLSID}) serve as the activation vehicle for out-of-process COM servers, making dllhost.exe spawning unexpected child processes a high-fidelity indicator. DCOM lateral movement communicates over TCP 135 (RPC Endpoint Mapper) before negotiating an ephemeral high port, distinguishing it from WMI or SMB-based lateral movement.

Microsoft Sentinel / Defender

kusto

let COMShells = dynamic(["cmd.exe", "powershell.exe", "pwsh.exe", "wscript.exe", "cscript.exe", "mshta.exe", "rundll32.exe", "regsvr32.exe"]);
let OfficeApps = dynamic(["excel.exe", "outlook.exe", "winword.exe", "powerpnt.exe", "onenote.exe"]);
DeviceProcessEvents
| where Timestamp > ago(24h)
| where FileName in~ (COMShells)
| where (
    // COM Surrogate (dllhost.exe /Processid:) spawning shells — primary DCOM remote activation indicator
    (InitiatingProcessFileName =~ "dllhost.exe" and InitiatingProcessCommandLine has "/Processid:")
    // MMC20.Application abuse — classic DCOM lateral movement vector documented by enigma0x3
    or (InitiatingProcessFileName =~ "mmc.exe" and FileName in~ ("cmd.exe", "powershell.exe", "pwsh.exe", "wscript.exe", "cscript.exe", "mshta.exe"))
    // Office application DCOM — Excel, Outlook, or Word spawning shells via COM interfaces
    or (InitiatingProcessFileName in~ (OfficeApps) and FileName in~ ("cmd.exe", "powershell.exe", "pwsh.exe", "wscript.exe", "cscript.exe", "mshta.exe"))
  )
| extend COMVector = case(
    InitiatingProcessFileName =~ "dllhost.exe", "COM_Surrogate_Activation",
    InitiatingProcessFileName =~ "mmc.exe", "MMC20_Application_DCOM",
    InitiatingProcessFileName in~ (OfficeApps), "Office_Application_DCOM",
    "Unknown_COM"
  )
| extend DCOMIndicator = InitiatingProcessCommandLine has_any ("/Processid:", "-Embedding")
| project Timestamp, DeviceName, AccountName, FileName, ProcessCommandLine,
         InitiatingProcessFileName, InitiatingProcessCommandLine,
         InitiatingProcessParentFileName, COMVector, DCOMIndicator
| sort by Timestamp desc

high severity medium confidence

Data Sources

Process: Process Creation Microsoft Defender for Endpoint

Required Tables

DeviceProcessEvents

False Positives

Legitimate IT administration tools using MMC snap-ins that internally spawn helper processes for managed operations (disk management, event viewer, device manager)
Software installation packages activating COM servers via dllhost.exe as part of normal registration workflows (MSI installers, COM+ application setup)
Microsoft Office macros performing legitimate document automation that spawn helper processes such as mail merge or report generation scripts
Remote management products (RMM tools, monitoring agents) that use DCOM as a transport mechanism for legitimate administrative operations on managed endpoints
COM+ application servers hosting business line applications that legitimately spawn worker processes via dllhost.exe as part of their normal operation

Splunk

spl

index=wineventlog sourcetype="XmlWinEventLog:Microsoft-Windows-Sysmon/Operational" EventCode=1
| where (ParentImage LIKE "%\\dllhost.exe" OR ParentImage LIKE "%\\mmc.exe" OR ParentImage LIKE "%\\excel.exe" OR ParentImage LIKE "%\\outlook.exe" OR ParentImage LIKE "%\\winword.exe" OR ParentImage LIKE "%\\powerpnt.exe")
| where (Image LIKE "%\\cmd.exe" OR Image LIKE "%\\powershell.exe" OR Image LIKE "%\\pwsh.exe" OR Image LIKE "%\\wscript.exe" OR Image LIKE "%\\cscript.exe" OR Image LIKE "%\\mshta.exe" OR Image LIKE "%\\rundll32.exe")
| eval IsCOMSurrogate=if(ParentImage LIKE "%\\dllhost.exe" AND CommandLine LIKE "%/Processid:%", 1, 0)
| eval IsMMCSpawn=if(ParentImage LIKE "%\\mmc.exe", 1, 0)
| eval IsOfficeSpawn=if(ParentImage LIKE "%\\excel.exe" OR ParentImage LIKE "%\\outlook.exe" OR ParentImage LIKE "%\\winword.exe" OR ParentImage LIKE "%\\powerpnt.exe", 1, 0)
| eval COMVector=case(IsCOMSurrogate=1, "COM_Surrogate_Activation", IsMMCSpawn=1, "MMC20_Application_DCOM", IsOfficeSpawn=1, "Office_Application_DCOM", true(), "Unknown_COM")
| eval DCOMIndicator=if(match(ParentCommandLine, "(?i)(/Processid:|-Embedding)"), 1, 0)
| table _time, host, User, Image, CommandLine, ParentImage, ParentCommandLine, COMVector, DCOMIndicator
| sort - _time

high severity medium confidence

Data Sources

Process: Process Creation Sysmon Event ID 1

Required Sourcetypes

XmlWinEventLog:Microsoft-Windows-Sysmon/Operational

False Positives

Legitimate IT administration tools using MMC snap-ins that internally spawn helper processes for managed operations
Software installation packages activating COM servers via dllhost.exe as part of normal registration workflows
Microsoft Office macros performing legitimate document automation that spawn helper processes
Remote management products using DCOM as a transport for legitimate administrative operations
COM+ application servers that legitimately spawn worker processes via dllhost.exe as part of business application hosting

IBM QRadar (AQL)

sql

SELECT
  DATEFORMAT(devicetime, 'yyyy-MM-dd HH:mm:ss') AS event_time,
  logsourcename(logsourceid) AS log_source,
  username,
  sourceip,
  QIDNAME(qid) AS event_name,
  "ParentImage",
  "ParentCommandLine",
  "Image",
  "CommandLine",
  CASE
    WHEN LOWER("ParentImage") LIKE '%\dllhost.exe' AND "ParentCommandLine" ILIKE '%/Processid:%' THEN 'COM_Surrogate_Activation'
    WHEN LOWER("ParentImage") LIKE '%\mmc.exe' THEN 'MMC20_Application_DCOM'
    WHEN LOWER("ParentImage") LIKE '%\excel.exe'
      OR LOWER("ParentImage") LIKE '%\outlook.exe'
      OR LOWER("ParentImage") LIKE '%\winword.exe'
      OR LOWER("ParentImage") LIKE '%\powerpnt.exe' THEN 'Office_Application_DCOM'
    ELSE 'Unknown_COM'
  END AS com_vector
FROM events
WHERE LOGSOURCETYPEID(logsourceid) IN (12, 119, 432)
  AND CATEGORYNAME(category) ILIKE '%process%'
  AND devicetime > NOW() - 1 DAYS
  AND (
    LOWER("Image") LIKE '%\cmd.exe'
    OR LOWER("Image") LIKE '%\powershell.exe'
    OR LOWER("Image") LIKE '%\pwsh.exe'
    OR LOWER("Image") LIKE '%\wscript.exe'
    OR LOWER("Image") LIKE '%\cscript.exe'
    OR LOWER("Image") LIKE '%\mshta.exe'
    OR LOWER("Image") LIKE '%\rundll32.exe'
    OR LOWER("Image") LIKE '%\regsvr32.exe'
  )
  AND (
    (LOWER("ParentImage") LIKE '%\dllhost.exe' AND "ParentCommandLine" ILIKE '%/Processid:%')
    OR LOWER("ParentImage") LIKE '%\mmc.exe'
    OR LOWER("ParentImage") LIKE '%\excel.exe'
    OR LOWER("ParentImage") LIKE '%\outlook.exe'
    OR LOWER("ParentImage") LIKE '%\winword.exe'
    OR LOWER("ParentImage") LIKE '%\powerpnt.exe'
  )
ORDER BY devicetime DESC

high severity medium confidence

Data Sources

QRadar Sysmon DSM QRadar Windows Security Event Log DSM Microsoft Windows Security Event Log

Required Tables

events

False Positives

Enterprise management platforms that use COM automation to drive Office applications for report generation or document conversion, legitimately spawning child processes
Legitimate PowerShell scripts executed through scheduled tasks that use COM interop to interact with Office or MMC snap-ins during normal IT operations
Software testing frameworks that invoke Office application COM interfaces (e.g., Selenium with Office interop, automated document processors) generating benign shell child processes

Sumo Logic CSE

sql

_sourceCategory=*windows* OR _sourceCategory=*sysmon* OR _sourceCategory=*endpoint*
| where EventID = "1" OR EventCode = "1"
| parse field=ParentImage "*\\*" as ParentPath, ParentProcess nodrop
| parse field=Image "*\\*" as ChildPath, ChildProcess nodrop
| where ChildProcess in ("cmd.exe", "powershell.exe", "pwsh.exe", "wscript.exe", "cscript.exe", "mshta.exe", "rundll32.exe", "regsvr32.exe")
| where (
    (toLowerCase(ParentProcess) = "dllhost.exe" and (ParentCommandLine contains "/Processid:" or ParentCommandLine contains "/processid:"))
    or toLowerCase(ParentProcess) = "mmc.exe"
    or toLowerCase(ParentProcess) in ("excel.exe", "outlook.exe", "winword.exe", "powerpnt.exe", "onenote.exe")
  )
| eval COMVector = if(toLowerCase(ParentProcess) = "dllhost.exe", "COM_Surrogate_Activation",
    if(toLowerCase(ParentProcess) = "mmc.exe", "MMC20_Application_DCOM",
      if(toLowerCase(ParentProcess) in ("excel.exe", "outlook.exe", "winword.exe", "powerpnt.exe", "onenote.exe"), "Office_Application_DCOM",
        "Unknown_COM")))
| eval DCOMIndicator = if(ParentCommandLine matches "(?i)(/Processid:|-Embedding)", "true", "false")
| fields _messageTime, Computer, User, Image, CommandLine, ParentImage, ParentCommandLine, COMVector, DCOMIndicator
| sort by _messageTime desc

high severity high confidence

Data Sources

Sumo Logic Installed Collector (Windows) Sysmon via Sumo Logic Windows Event Source Sumo Logic Cloud SIEM Enterprise (CSE)

Required Tables

Windows Event Log (Sysmon EventID 1)

False Positives

Legitimate COM-based administrative automation using dllhost.exe surrogate processes for out-of-process COM server activation during standard software installations or updates
Microsoft Management Console (mmc.exe) extensions or snap-ins that programmatically launch PowerShell or cmd.exe for configuration operations as part of authorized IT administration
Business process automation solutions that use Office DCOM interfaces (e.g., document generation pipelines, data extraction workflows) and legitimately spawn child processes during operation

Google Chronicle / SecOps

yaral

rule t1175_com_dcom_abuse {
  meta:
    author = "Argus Detection Engineering"
    description = "Detects COM and DCOM abuse (T1175) — shell processes spawned from COM surrogate dllhost.exe, MMC20.Application, or Office application DCOM interfaces indicating local COM execution or DCOM lateral movement"
    mitre_attack_tactic = "Lateral Movement, Execution"
    mitre_attack_technique = "T1175"
    severity = "HIGH"
    confidence = "HIGH"

  events:
    $e.metadata.event_type = "PROCESS_LAUNCH"
    $e.principal.process.file.full_path = /(?i)(cmd\.exe|powershell\.exe|pwsh\.exe|wscript\.exe|cscript\.exe|mshta\.exe|rundll32\.exe|regsvr32\.exe)$/
    (
      (
        $e.principal.process.parent_process.file.full_path = /(?i)\\dllhost\.exe$/
        and $e.principal.process.parent_process.command_line = /(?i)\/Processid:/
      )
      or $e.principal.process.parent_process.file.full_path = /(?i)\\mmc\.exe$/
      or $e.principal.process.parent_process.file.full_path = /(?i)\\(excel|outlook|winword|powerpnt|onenote)\.exe$/
    )

  match:
    $e.principal.hostname over 5m

  outcome:
    $risk_score = max(
      if($e.principal.process.parent_process.file.full_path = /(?i)\\dllhost\.exe$/ and $e.principal.process.parent_process.command_line = /(?i)\/Processid:/, 95,
        if($e.principal.process.parent_process.file.full_path = /(?i)\\mmc\.exe$/, 85, 75))
    )
    $com_vector = if(
      $e.principal.process.parent_process.file.full_path = /(?i)\\dllhost\.exe$/, "COM_Surrogate_Activation",
      if($e.principal.process.parent_process.file.full_path = /(?i)\\mmc\.exe$/, "MMC20_Application_DCOM", "Office_Application_DCOM")
    )
    $target_host = $e.principal.hostname
    $user = $e.principal.user.userid
    $child_process = $e.principal.process.command_line
    $parent_cmdline = $e.principal.process.parent_process.command_line

  condition:
    $e
}

high severity high confidence

Data Sources

Chronicle UDM (Unified Data Model) Google Chronicle SIEM Sysmon forwarded via Chronicle ingestion

Required Tables

PROCESS_LAUNCH UDM events

False Positives

Authorized use of COM surrogate processes by Windows subsystems for legitimate out-of-process COM server activation during software installation, thumbnail generation, or shell extension loading
System administration scripts that programmatically interact with MMC snap-ins (e.g., AD management, GPO editing) via mmc.exe COM interface, resulting in benign shell child process creation
Automated document processing pipelines using Office application COM automation (VBA macro execution, mail merge, report generation) that spawn cmd.exe or PowerShell as part of their documented workflow

Last updated: 2026-04-18 Research depth: deep

References (12)

Response Playbook

1. Examine the full command line and decode any Base64 content...
2. Identify the parent process chain and user context...
3. Check for concurrent network connections from the process...

Investigation Guide

Related techniques: T1027, T1105, T1562.001...
Forensic artifacts: PSReadLine history, Prefetch, ScriptBlock logs...

Atomic Red Team Tests

Test 1: Encoded command execution...
Test 2: Download cradle via Net.WebClient...

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Component Object Model and Distributed COM

Data Sources

Required Tables

False Positives

Data Sources

Required Sourcetypes

False Positives

Data Sources

Required Tables

False Positives

Data Sources

Required Tables

False Positives

Data Sources

Required Tables

False Positives

Data Sources

Required Tables

False Positives

Data Sources

Required Tables

False Positives

Response Playbook

Investigation Guide

Atomic Red Team Tests

Unlock Pro Content

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