splunk-security_content/docs/_posts/2021-06-02-wbemprox_com_object_execution.md

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title	excerpt	categories	last_modified_at	toc	toc_label	tags
Wbemprox COM Object Execution	Signed Binary Proxy Execution, CMSTP	Endpoint	2021-06-02	true		Signed Binary Proxy Execution Defense Evasion CMSTP Defense Evasion Splunk Enterprise Splunk Enterprise Security Splunk Cloud Endpoint

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Description

this search is designed to detect potential malicious process loading COM object to wbemprox.dll,

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint
• Last Updated: 2021-06-02
• Author: Teoderick Contreras, Splunk
• ID: 9d911ce0-c3be-11eb-b177-acde48001122

ATT&CK

ID	Technique	Tactic
T1218	Signed Binary Proxy Execution	Defense Evasion

| T1218.003 | CMSTP | Defense Evasion |

Search

`sysmon` EventCode=7  ImageLoaded IN ("*\\fastprox.dll", "*\\wbemprox.dll", "*\\wbemcomn.dll") NOT (process_name IN ("wmiprvse.exe", "WmiApSrv.exe", "unsecapp.exe")) NOT(Image IN("*\\windows\\*","*\\program files*", "*\\wbem\\*")) 
| stats count min(_time) as firstTime max(_time) as lastTime by Image ImageLoaded process_name Computer EventCode Signed ProcessId Hashes IMPHASH 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `wbemprox_com_object_execution_filter`

Associated Analytic Story

• Ransomware
• Revil Ransomware

How To Implement

To successfully implement this search, you need to be ingesting logs with the process name and imageloaded executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.

Required field

• _time
• Image
• ImageLoaded
• process_name
• Computer
• EventCode
• Signed
• ProcessId
• Hashes
• IMPHASH

Kill Chain Phase

• Exploitation

Known False Positives

legitimate process that are not in the exception list may trigger this event.

RBA

Risk Score	Impact	Confidence	Message
35.0	70	50	Suspicious COM Object Execution on Computer

Reference

• https://krebsonsecurity.com/2021/05/a-closer-look-at-the-darkside-ransomware-gang/
• https://www.mcafee.com/blogs/other-blogs/mcafee-labs/mcafee-atr-analyzes-sodinokibi-aka-revil-ransomware-as-a-service-what-the-code-tells-us/

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

• https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/revil/inf2/windows-sysmon.log

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