Certutil exe certificate extraction
Description
The following analytic identifies the use of certutil.exe with arguments indicating the manipulation or extraction of certificates. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names and command-line arguments. This activity is significant because extracting certificates can allow attackers to sign new authentication tokens, particularly in federated environments like Windows ADFS. If confirmed malicious, this could enable attackers to forge authentication tokens, potentially leading to unauthorized access and privilege escalation within the network.
Query · spl
| tstats `security_content_summariesonly`
count min(_time) as firstTime
max(_time) as lastTime
FROM datamodel=Endpoint.Processes
WHERE
(
Processes.process_name=certutil.exe
OR
Processes.original_file_name=certutil.exe
)
Processes.process = "*-exportPFX*"
BY Processes.action Processes.dest Processes.original_file_name
Processes.parent_process Processes.parent_process_exec
Processes.parent_process_guid Processes.parent_process_id
Processes.parent_process_name Processes.parent_process_path
Processes.process Processes.process_exec Processes.process_guid
Processes.process_hash Processes.process_id Processes.process_integrity_level
Processes.process_name Processes.process_path Processes.user
Processes.user_id Processes.vendor_product
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `certutil_exe_certificate_extraction_filter`
Implementation guide
The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
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.
Analyst notes
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.