DiskShadow.exe is a Microsoft Signed binary present on Windows Server. It has a scripting mode intended for complex scripted backup operations. This feature also allows for execution of arbitrary unsigned code. This analytic looks for the usage of the scripting mode flags in executions of DiskShadow. During triage, compare to known backup behavior in your environment and then review the scripts called by diskshadow.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2022-02-15
- Author: Lou Stella, Splunk
- ID: 58adae9e-8ea3-11ec-90f6-acde48001122
Kill Chain Phase
- CIS 10
1 2 3 4 5 6 | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_diskshadow` (Processes.process=*-s* OR Processes.process=*/s*) 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)` | `security_content_ctime(lastTime)` | `windows_diskshadow_proxy_execution_filter`
The SPL above uses the following Macros:
windows_diskshadow_proxy_execution_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
How To Implement
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 using the DiskShadow tool in their infrastructure as a main backup tool with scripts will cause false positives that can be filtered with
Associated Analytic Story
|49.0||70||70||Possible Signed Binary Proxy Execution 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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