Detection rules › Sigma
Suspicious WmiPrvSE Child Process
Detects suspicious and uncommon child processes of WmiPrvSE
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Execution | T1047 Windows Management Instrumentation, T1204.002 User Execution: Malicious File |
| Stealth | T1218.010 System Binary Proxy Execution: Regsvr32 |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 1 | Process creation |
| Security-Auditing | Event ID 4688 | A new process has been created. |
Rule body yaml
title: Suspicious WmiPrvSE Child Process
id: 8a582fe2-0882-4b89-a82a-da6b2dc32937
related:
- id: 692f0bec-83ba-4d04-af7e-e884a96059b6
type: similar
- id: d21374ff-f574-44a7-9998-4a8c8bf33d7d
type: similar
- id: 18cf6cf0-39b0-4c22-9593-e244bdc9a2d4
type: obsolete
status: test
description: Detects suspicious and uncommon child processes of WmiPrvSE
references:
- https://thedfirreport.com/2021/03/29/sodinokibi-aka-revil-ransomware/
- https://github.com/vadim-hunter/Detection-Ideas-Rules/blob/02bcbfc2bfb8b4da601bb30de0344ae453aa1afe/Threat%20Intelligence/The%20DFIR%20Report/20210329_Sodinokibi_(aka_REvil)_Ransomware.yaml
- https://blog.osarmor.com/319/onenote-attachment-delivers-asyncrat-malware/
- https://twitter.com/ForensicITGuy/status/1334734244120309760
author: Vadim Khrykov (ThreatIntel), Cyb3rEng, Florian Roth (Nextron Systems)
date: 2021-08-23
modified: 2023-11-10
tags:
- attack.execution
- attack.stealth
- attack.t1047
- attack.t1204.002
- attack.t1218.010
logsource:
product: windows
category: process_creation
detection:
selection_parent:
ParentImage|endswith: '\wbem\WmiPrvSE.exe'
selection_children_1:
# TODO: Add more LOLBINs or suspicious processes that make sens in your environment
Image|endswith:
- '\certutil.exe'
- '\cscript.exe'
- '\mshta.exe'
- '\msiexec.exe'
- '\regsvr32.exe'
- '\rundll32.exe'
- '\verclsid.exe'
- '\wscript.exe'
selection_children_2:
# This is in a separate selection due to the nature of FP generated with CMD
Image|endswith: '\cmd.exe'
CommandLine|contains:
- 'cscript'
- 'mshta'
- 'powershell'
- 'pwsh'
- 'regsvr32'
- 'rundll32'
- 'wscript'
filter_main_werfault:
Image|endswith: '\WerFault.exe'
filter_main_wmiprvse:
Image|endswith: '\WmiPrvSE.exe' # In some legitimate case WmiPrvSE was seen spawning itself
filter_main_msiexec:
Image|endswith: '\msiexec.exe'
CommandLine|contains: '/i '
condition: selection_parent and 1 of selection_children_* and not 1 of filter_main_*
falsepositives:
- Unknown
level: high
Stages and Predicates
Stage 0: condition
selection_parent and 1 of selection_children_* and not 1 of filter_main_*Stage 1: selection_parent
selection_parent:
ParentImage|endswith: '\wbem\WmiPrvSE.exe'
Stage 2: selection_children_1
selection_children_1:
Image|endswith:
- '\certutil.exe'
- '\cscript.exe'
- '\mshta.exe'
- '\msiexec.exe'
- '\regsvr32.exe'
- '\rundll32.exe'
- '\verclsid.exe'
- '\wscript.exe'
Stage 3: selection_children_2
selection_children_2:
Image|endswith: '\cmd.exe'
CommandLine|contains:
- 'cscript'
- 'mshta'
- 'powershell'
- 'pwsh'
- 'regsvr32'
- 'rundll32'
- 'wscript'
Stage 4: not filter_main_*
filter_main_werfault:
Image|endswith: '\WerFault.exe'
filter_main_wmiprvse:
Image|endswith: '\WmiPrvSE.exe'
filter_main_msiexec:
Image|endswith: '\msiexec.exe'
CommandLine|contains: '/i '
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
CommandLine | match | /i |
Image | ends_with | \msiexec.exe |
Image | ends_with | \WerFault.exe |
Image | ends_with | \WmiPrvSE.exe |
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 |
|---|---|---|
CommandLine | match |
|
Image | ends_with |
|
ParentImage | ends_with |
|