Detection rules › Sigma
DLL Loaded From Suspicious Location Via Cmspt.EXE
Detects cmstp loading "dll" or "ocx" files from suspicious locations
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Stealth | T1218.003 System Binary Proxy Execution: CMSTP |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 7 | Image loaded |
Rule body yaml
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
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
Image | ends_with |
|
ImageLoaded | ends_with |
|
ImageLoaded | match |
|