Windows Impair Defense Add Xml Applocker Rules
Description
The following analytic detects the use of a PowerShell commandlet to import an AppLocker XML policy. This behavior is identified by monitoring processes that execute the "Import-Module Applocker" and "Set-AppLockerPolicy" commands with the "-XMLPolicy" parameter. This activity is significant because it can indicate an attempt to disable or bypass security controls, as seen in the Azorult malware. If confirmed malicious, this could allow an attacker to disable antivirus products, leading to further compromise and persistence within the environment.
Query · spl
| tstats `security_content_summariesonly` values(Processes.process) as process min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
WHERE `process_powershell`
AND
Processes.process="*Import-Module Applocker*"
AND
Processes.process="*Set-AppLockerPolicy *"
AND
Processes.process="* -XMLPolicy *"
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)`
| `windows_impair_defense_add_xml_applocker_rules_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
- Administrators may execute this command that may cause some false positive.
Analyst notes
Known false positives: Administrators may execute this command that may cause some false positive.