Detect Distributed Component Object Model in Sumo Logic CSE
Adversaries may use Valid Accounts to interact with remote machines by taking advantage of Distributed Component Object Model (DCOM). DCOM extends Windows COM (Component Object Model) beyond local machines using RPC, allowing remote method calls on COM objects. Adversaries with Administrator privileges can remotely obtain code execution through Office applications (Excel, Outlook), MMC20.Application, ShellWindows, and other insecure COM objects. Tools like Empire's Invoke-DCOM, Cobalt Strike, and SILENTTRINITY have built-in DCOM lateral movement capabilities. DCOM communicates over TCP port 135 (RPC endpoint mapper) and dynamically assigned high ports.
MITRE ATT&CK
- Tactic
- Lateral Movement
- Technique
- T1021 Remote Services
- Sub-technique
- T1021.003 Distributed Component Object Model
- Canonical reference
- https://attack.mitre.org/techniques/T1021/003/
Sumo Detection Query
_sourceCategory=*windows/sysmon* OR _sourceCategory=*wineventlog*
| where EventCode = "1" OR EventCode = "4688"
| parse regex field=ParentImage "(?i)(?<ParentProcessName>[^\\\\]+)$" nodrop
| parse regex field=Image "(?i)(?<ChildProcessName>[^\\\\]+)$" nodrop
| toLowerCase(ParentProcessName) as parent_proc
| toLowerCase(ChildProcessName) as child_proc
| where (
(
parent_proc in ("mmc.exe", "excel.exe", "winword.exe", "outlook.exe", "powerpnt.exe", "visio.exe")
AND child_proc in ("cmd.exe", "powershell.exe", "wscript.exe", "cscript.exe", "mshta.exe", "rundll32.exe", "regsvr32.exe", "certutil.exe")
)
OR child_proc = "dcomcnfg.exe"
OR (CommandLine matches "*DCOM*" AND CommandLine matches "*-Exec*")
)
| if (child_proc = "dcomcnfg.exe", "DCOM_ConfigTool",
if (parent_proc in ("mmc.exe", "excel.exe", "winword.exe", "outlook.exe", "powerpnt.exe"),
"COM_SuspiciousChild", "DCOM_CommandLineRef")) as DetectionPattern
| count as EventCount by _messageTime, Computer, User, Image, CommandLine, ParentImage, ParentCommandLine, DetectionPattern
| fields -EventCount
| sort by _messageTime descDetects DCOM lateral movement in Sumo Logic by parsing Windows Sysmon Event ID 1 or Security Event ID 4688 process creation logs for suspicious child processes spawned from known COM host applications. Extracts process names from full image paths using regex, then classifies findings into detection patterns. Requires Sysmon or Windows Security log source categories.
Data Sources
Required Tables
False Positives & Tuning
- Enterprise software deployment via SCCM that uses Office COM objects to deliver or configure applications, spawning cmd.exe or PowerShell as child processes
- Automated reporting systems in finance organizations where Excel macros legitimately spawn wscript.exe to process or export data files on schedule
- IT operations tooling (e.g. Ansible WinRM modules, SaltStack) that uses mmc.exe as an entry point for remote configuration management tasks
- Help desk remote support sessions using legitimate DCOM-based remote management tools that trigger these parent-child process relationships
Other platforms for T1021.003
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1DCOM Lateral Movement via MMC20.Application
Expected signal: Sysmon Event ID 1: powershell.exe process with MMC20.Application in command line. Sysmon Event ID 3: outbound connection to 127.0.0.1 on port 135 and dynamic RPC port. Sysmon Event ID 1 on target: mmc.exe spawning cmd.exe. Sysmon Event ID 11: dcom_test.txt file created in C:\Windows\Temp.
- Test 2DCOM Lateral Movement via ShellWindows
Expected signal: Sysmon Event ID 1: powershell.exe with CLSID 9BA05972 in command line. Sysmon Event ID 3: connection to 127.0.0.1:135. Sysmon Event ID 1: explorer.exe or svchost spawning cmd.exe on the target.
- Test 3Query DCOM Configuration via dcomcnfg
Expected signal: Sysmon Event ID 1: Process Create for dcomcnfg.exe. Security Event ID 4688 (if command-line auditing enabled). The process tree will show dcomcnfg.exe spawning mmc.exe as a child.
References (7)
- https://attack.mitre.org/techniques/T1021/003/
- https://enigma0x3.net/2017/01/05/lateral-movement-using-the-mmc20-application-com-object/
- https://enigma0x3.net/2017/01/23/lateral-movement-via-dcom-round-2/
- https://www.fireeye.com/blog/threat-research/2019/06/hunting-com-objects.html
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1021.003/T1021.003.md
- https://github.com/EmpireProject/Empire/blob/master/data/module_source/lateral_movement/Invoke-DCOM.ps1
- https://learn.microsoft.com/en-us/windows/win32/com/the-component-object-model
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