This analytic will identify a suspicious process command-line related to Windows Defender exclusion feature. This command is abused by adversaries, malware authors and red teams to bypass Windows Defender Antivirus products by excluding folder path, file path, process and extensions. From its real time or schedule scan to execute their malicious code. This is a good indicator for defense evasion and to look further for events after this behavior.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint- Datasource: Splunk Add-on for Sysmon
- Last Updated: 2021-11-25
- Author: Teoderick Contreras, Splunk
- ID: 773b66fe-4dd9-11ec-8289-acde48001122
Kill Chain Phase
1 2 3 4 5 6 | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where (Processes.process = "*Add-MpPreference *" OR Processes.process = "*Set-MpPreference *") AND Processes.process="*-exclusion*" by Processes.dest Processes.user Processes.parent_process Processes.parent_process_name Processes.process_name Processes.original_file_name Processes.process Processes.process_id Processes.parent_process_id | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `add_or_set_windows_defender_exclusion_filter`
The SPL above uses the following Macros:
add_or_set_windows_defender_exclusion_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
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
Registry node. Also make sure that this registry was included in your config files ex. sysmon config to be monitored.
Known False Positives
Admin or user may choose to use this windows features. Filter as needed.
Associated Analytic story
|64.0||80||80||exclusion command $process$ executed on $dest$|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
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