splunk-security_content/docs/_posts/2021-09-29-verclsid_clsid_execution.md

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title	excerpt	categories	last_modified_at	toc	toc_label	tags
Verclsid CLSID Execution	Verclsid, Signed Binary Proxy Execution	Endpoint	2021-09-29	true		Verclsid Defense Evasion Signed Binary Proxy Execution Defense Evasion Splunk Enterprise Splunk Enterprise Security Splunk Cloud Endpoint

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Description

This analytic is to detect a possible abuse of verclsid to execute malicious file through generate CLSID. This process is a normal application of windows to verify the CLSID COM object before it is instantiated by Windows Explorer. This hunting query can be a good pivot point to analyze what is he CLSID or COM object pointing too to check if it is a valid application or not.

• Type: Hunting
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint
• Last Updated: 2021-09-29
• Author: Teoderick Contreras, Splunk
• ID: 61e9a56a-20fa-11ec-8ba3-acde48001122

ATT&CK

ID	Technique	Tactic
T1218.012	Verclsid	Defense Evasion

| T1218 | Signed Binary Proxy Execution | Defense Evasion |

Search

| tstats `security_content_summariesonly` values(Processes.process) as process values(Processes.parent_process) as parent_process values(Processes.process_id) as process_id count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_verclsid` AND Processes.process="*/S*" Processes.process="*/C*" AND  Processes.process="*{*" AND Processes.process="*}*" by  Processes.process_name Processes.original_file_name Processes.dest Processes.user Processes.parent_process_name Processes.parent_process 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `verclsid_clsid_execution_filter`

Associated Analytic Story

• Unusual Processes

How To Implement

To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint datamodel in the Processes node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.

Required field

• _time
• Processes.dest
• Processes.user
• Processes.parent_process_name
• Processes.parent_process
• Processes.original_file_name
• Processes.process_name
• Processes.process
• Processes.process_id
• Processes.parent_process_path
• Processes.process_path
• Processes.parent_process_id

Kill Chain Phase

• Exploitation

Known False Positives

windows can used this application for its normal COM object validation.

RBA

Risk Score	Impact	Confidence	Message
25.0	50	50	process process_name to execute possible clsid commandline process in dest

Reference

• https://gist.github.com/NickTyrer/0598b60112eaafe6d07789f7964290d5
• https://bohops.com/2018/08/18/abusing-the-com-registry-structure-part-2-loading-techniques-for-evasion-and-persistence/

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/attack_techniques/T1218.012/verclsid_exec/sysmon.log

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