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: Anomaly
- Product: Splunk Behavioral Analytics
- Datamodel: Endpoint_Processes
- Last Updated: 2022-02-17
- Author: Lou Stella, Splunk
- ID: aa502688-9037-11ec-842d-acde48001122
Kill Chain Phase
- CIS 8
1 2 3 4 5 6 7 8 | from read_ssa_enriched_events() | where "Endpoint_Processes" IN(_datamodels) | eval timestamp=parse_long(ucast(map_get(input_event, "_time"), "string", null)), cmd_line=lower(ucast(map_get(input_event, "process"), "string", null)), process_name=lower(ucast(map_get(input_event, "process_name"), "string", null)), process_path=ucast(map_get(input_event, "process_path"), "string", null), parent_process_name=ucast(map_get(input_event, "parent_process_name"), "string", null), event_id=ucast(map_get(input_event, "event_id"), "string", null) | where cmd_line IS NOT NULL AND process_name IS NOT NULL AND process_name="diskshadow.exe" AND (like (cmd_line, "%-s%") OR like (cmd_line, "%/s%")) | eval start_time=timestamp, end_time=timestamp, entities=mvappend(ucast(map_get(input_event, "dest_user_id"), "string", null), ucast(map_get(input_event, "dest_device_id"), "string", null)) | eval body=create_map(["event_id", event_id, "cmd_line", cmd_line, "process_name", process_name, "parent_process_name", parent_process_name, "process_path", process_path]) | into write_ssa_detected_events();
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
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
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
|49.0||70||70||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.|
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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