Detection: Windows Diskshadow Proxy Execution

Date: 2022-02-17 ID: aa502688-9037-11ec-842d-acde48001122 Author: Lou Stella, Splunk Type: Anomaly Product: Splunk User Behavior Analytics

Description

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.

Annotations

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Implementation

To successfully implement this search you need to be ingesting information on processes that include the name of the process responsible for the changes from your endpoints into the Endpoint_Processess datamodel.

Known False Positives

Administrators using the DiskShadow tool in their infrastructure as a main backup tool with scripts will cause false positives

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest_device_id$ by user $dest_user_id$ attempting to run a script. 49 70 70
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Version: 4