WMI Module Load¶

Metadata¶


collaborators	[‘@Cyb3rWard0g’, ‘@Cyb3rPandaH’]
creation date	2019/08/11
modification date	2020/09/20
playbook related	[]

Hypothesis¶

Adversaries might be leveraging WMI modules to execute WMI tasks bypassing controls monitoring for wmiprvse.exe or wmiapsrv.exe activity

Technical Context¶

WMI is the Microsoft implementation of the Web-Based Enterprise Management (WBEM) and Common Information Model (CIM). Both standards aim to provide an industry-agnostic means of collecting and transmitting information related to any managed component in an enterprise. An example of a managed component in WMI would be a running process, registry key, installed service, file information, etc. At a high level, Microsoft’s implementation of these standards can be summarized as follows > Managed Components Managed components are represented as WMI objects — class instances representing highly structured operating system data. Microsoft provides a wealth of WMI objects that communicate information related to the operating system. E.g. Win32_Process, Win32_Service, AntiVirusProduct, Win32_StartupCommand, etc. WMI modules loaded by legit processes such as wmiprvse.exe or wmiapsrv.exe are the following

C:\Windows\System32\wmiclnt.dll C:\Windows\System32\wbem\WmiApRpl.dll C:\Windows\System32\wbem\wmiprov.dll C:\Windows\System32\wbem\wmiutils.dll

Offensive Tradecraft¶

Adversaries could leverage the WMI modules above to execute WMI tasks bypassing controls looking for wmiprvse.exe or wmiapsrv.exe activity.

Mordor Test Data¶


metadata	https://mordordatasets.com/notebooks/small/windows/05_defense_evasion/SDWIN-190518200432.html
link	https://raw.githubusercontent.com/OTRF/mordor/master/datasets/small/windows/defense_evasion/host/empire_psinject_PEinjection.zip

Analytics¶

Initialize Analytics Engine¶

from openhunt.mordorutils import *
spark = get_spark()

Download & Process Mordor Dataset¶

mordor_file = "https://raw.githubusercontent.com/OTRF/mordor/master/datasets/small/windows/defense_evasion/host/empire_psinject_PEinjection.zip"
registerMordorSQLTable(spark, mordor_file, "mordorTable")

[+] Processing a Spark DataFrame..
[+] DataFrame Returned !
[+] Temporary SparkSQL View: mordorTable 

Analytic I¶

Look for processes (non wmiprvse.exe or WmiApSrv.exe) loading wmi modules

Data source	Event Provider	Relationship	Event
Module	Microsoft-Windows-Sysmon/Operational	Process loaded Dll	7

df = spark.sql(
'''
SELECT `@timestamp`, Hostname, Image, ImageLoaded
FROM mordorTable
WHERE Channel = "Microsoft-Windows-Sysmon/Operational"
    AND EventID = 7
    AND (
        lower(ImageLoaded) LIKE "%wmiclnt.dll"
        OR lower(ImageLoaded) LIKE "%WmiApRpl.dll"
        OR lower(ImageLoaded) LIKE "%wmiprov.dll"
        OR lower(ImageLoaded) LIKE "%wmiutils.dll"
        OR lower(ImageLoaded) LIKE "%wbemcomn.dll"
        OR lower(ImageLoaded) LIKE "%WMINet_Utils.dll"
        OR lower(ImageLoaded) LIKE "%wbemsvc.dll"
        OR lower(ImageLoaded) LIKE "%fastprox.dll"
        OR lower(Description) LIKE "%wmi%"
    )
    AND NOT (
        lower(Image) LIKE "%wmiprvse.exe"
        OR lower(Image) LIKE "%wmiapsrv.exe"
        OR lower(Image) LIKE "%svchost.exe"
    )
'''
)
df.show(10,False)

+-----------------------+---------------------------+-------------------------------+----------------------------------------------------------------+
|@timestamp             |Hostname                   |Image                          |ImageLoaded                                                     |
+-----------------------+---------------------------+-------------------------------+----------------------------------------------------------------+
|2020-08-07 14:32:49.233|WORKSTATION5.theshire.local|C:\Windows\System32\notepad.exe|C:\Windows\System32\wbem\wmiutils.dll                           |
|2020-08-07 14:32:49.24 |WORKSTATION5.theshire.local|C:\Windows\System32\notepad.exe|C:\Windows\System32\wbemcomn.dll                                |
|2020-08-07 14:32:49.251|WORKSTATION5.theshire.local|C:\Windows\System32\notepad.exe|C:\Windows\System32\wbem\wbemprox.dll                           |
|2020-08-07 14:32:49.253|WORKSTATION5.theshire.local|C:\Windows\System32\notepad.exe|C:\Windows\Microsoft.NET\Framework64\v4.0.30319\WMINet_Utils.dll|
|2020-08-07 14:32:49.279|WORKSTATION5.theshire.local|C:\Windows\System32\notepad.exe|C:\Windows\System32\wbem\wbemsvc.dll                            |
|2020-08-07 14:32:49.286|WORKSTATION5.theshire.local|C:\Windows\System32\notepad.exe|C:\Windows\System32\wbem\fastprox.dll                           |
+-----------------------+---------------------------+-------------------------------+----------------------------------------------------------------+

Known Bypasses¶

Idea	Playbook

False Positives¶

None

Hunter Notes¶

Stack the processes loading WMI modules and document the activity in your environment.
Stack child processes (if any) of non wmiprvse.exe loading wmi modules

Hunt Output¶

Type	Link
Sigma Rule	https://github.com/OTRF/ThreatHunter-Playbook/blob/master/signatures/sigma/sysmon_wmi_module_load.yml

References¶

https://posts.specterops.io/threat-hunting-with-jupyter-notebooks-part-4-sql-join-via-apache-sparksql-6630928c931e
https://posts.specterops.io/real-time-sysmon-processing-via-ksql-and-helk-part-3-basic-use-case-8fbf383cb54f

Threat Hunter Playbook