splunk-security_content/docs/_posts/2021-01-26-certutil_exe_certificate_extraction.md

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title	excerpt	categories	last_modified_at	toc	toc_label	tags
Certutil exe certificate extraction		Endpoint	2021-01-26	true		Splunk Enterprise Splunk Enterprise Security Splunk Cloud Endpoint

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Description

This search looks for arguments to certutil.exe indicating the manipulation or extraction of Certificate. This certificate can then be used to sign new authentication tokens specially inside Federated environments such as Windows ADFS.

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint
• Last Updated: 2021-01-26
• Author: Rod Soto, Splunk
• ID: 337a46be-600f-11eb-ae93-0242ac130002

Search

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name=certutil.exe Processes.process = "*-exportPFX*" by Processes.dest Processes.user Processes.parent_process Processes.process_name Processes.process Processes.process_id Processes.parent_process_id 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `certutil_exe_certificate_extraction_filter`

Associated Analytic Story

• Windows Persistence Techniques
• Cloud Federated Credential Abuse

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.

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

• Installation

Known False Positives

Unless there are specific use cases, manipulating or exporting certificates using certutil is uncommon. Extraction of certificate has been observed during attacks such as Golden SAML and other campaigns targeting Federated services.

RBA

Risk Score	Impact	Confidence	Message
63.0	90	70	An instance of parent_process_name spawning process_name was identified on endpoint dest by user user attempting export a certificate.

Reference

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/suspicious_behaviour/certutil_exe_certificate_extraction/windows-sysmon.log

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