Detection rules › Sigma
DLL Loaded From Suspicious Location Via Cmspt.EXE
Detects cmstp loading "dll" or "ocx" files from suspicious locations
Known false positives
- Unikely
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Stealth |
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Sysmon | Event ID 7: Image loaded |
Rule body
title: DLL Loaded From Suspicious Location Via Cmspt.EXE
id: 75e508f7-932d-4ebc-af77-269237a84ce1
status: test
description: Detects cmstp loading "dll" or "ocx" files from suspicious locations
references:
- https://github.com/vadim-hunter/Detection-Ideas-Rules/blob/02bcbfc2bfb8b4da601bb30de0344ae453aa1afe/TTPs/Defense%20Evasion/T1218%20-%20Signed%20Binary%20Proxy%20Execution/T1218.003%20-%20CMSTP/Procedures.yaml
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-08-30
modified: 2023-02-17
tags:
- attack.stealth
- attack.t1218.003
logsource:
category: image_load
product: windows
detection:
selection:
Image|endswith: '\cmstp.exe'
ImageLoaded|contains:
# Add more suspicious paths as you see fit in your env
- '\PerfLogs\'
- '\ProgramData\'
- '\Users\'
- '\Windows\Temp\'
- 'C:\Temp\'
ImageLoaded|endswith:
- '.dll'
- '.ocx'
condition: selection
falsepositives:
- Unikely
level: high
Stages and Predicates
Stage 0: condition
selectionStage 1: selection
selection:
Image|endswith: '\cmstp.exe'
ImageLoaded|contains:
- '\PerfLogs\'
- '\ProgramData\'
- '\Users\'
- '\Windows\Temp\'
- 'C:\Temp\'
ImageLoaded|endswith:
- '.dll'
- '.ocx'
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
Image | ends_with |
| field:"Image" kind:ends_with value:"\cmstp.exe" |
ImageLoaded | ends_with |
| field:"ImageLoaded" kind:ends_with |
ImageLoaded | match |
| field:"ImageLoaded" kind:match |