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detections/endpoint/ssa___windows_diskshadow_proxy_execution.yml

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+name: Windows Diskshadow Proxy Execution
+id: aa502688-9037-11ec-842d-acde48001122
+version: 1
+date: '2022-02-17'
+author: Lou Stella, Splunk
+type: Anomaly
+datamodel:
+- Endpoint_Processes
+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. 
+search: '| 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();'
+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 `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
+references:
+-  https://bohops.com/2018/03/26/diskshadow-the-return-of-vss-evasion-persistence-and-active-directory-database-extraction/
+tags:
+  analytic_story:
+  - Living Off The Land
+  dataset:
+  - https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1218/diskshadow/windows-security.log
+  kill_chain_phases:
+  - Exploitation
+  mitre_attack_id:
+  - T1218
+  product:
+  - Splunk Behavioral Analytics
+  required_fields:
+  - _time
+  - dest_device_id
+  - process_name
+  - parent_process_name
+  - process_path
+  - dest_user_id
+  - process
+  - cmd_line
+  security_domain: endpoint
+  impact: 70
+  confidence: 70 
+  risk_score: 49
+  context:
+  - Source:Endpoint
+  - Stage:Execution
+  message: 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.
+  observable:
+  - name: dest_device_id
+    type: Hostname
+    role:
+    - Victim
+  - name: dest_user_id
+    type: User
+    role:
+    - Victim
+  - name: parent_process_name
+    type: Parent Process
+    role:
+    - Parent Process
+  - name: process_name
+    type: Process
+    role:
+    - Child Process
+  nist:
+  - DE.CM
+  cis20:
+  - CIS 8

tests/endpoint/ssa___windows_diskshadow_proxy_execution.test.yml

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+name: BA Windows Diskshadow Proxy Execution Unit Test
+tests:
+- name: BA Windows Diskshadow Proxy Execution
+  file: endpoint/ssa___windows_diskshadow_proxy_execution.yml
+  pass_condition: '@count_gt(0)'
+  attack_data:
+  - file_name: windows-security.log
+    data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1218/diskshadow/windows-security.log
+    source: WinEventLog:Security