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Description

This detection detects a high amount of office file copied. This can be an indicator for a malicious insider.

  • Type: Anomaly
  • Product: Splunk Behavioral Analytics
  • Datamodel: Endpoint_Filesystem
  • Last Updated: 2021-12-07
  • Author: Patrick Bareiss, Splunk
  • ID: 3c6594a9-8df6-45a1-9357-d73b62083c63

ATT&CK

ID Technique Tactic
T1048.003 Exfiltration Over Unencrypted/Obfuscated Non-C2 Protocol Exfiltration

| from read_ssa_enriched_events() 
| eval timestamp=parse_long(ucast(map_get(input_event, "_time"), "string", null)) 
| eval action=ucast(map_get(input_event, "action"), "string", null), process=ucast(map_get(input_event, "process"), "string", null), file_name=ucast(map_get(input_event, "file_name"), "string", null), file_path=ucast(map_get(input_event, "file_path"), "string", null), dest_user_id=ucast(map_get(input_event, "dest_user_id"), "string", null), dest_device_id=ucast(map_get(input_event, "dest_device_id"), "string", null) 
| where "Endpoint_Filesystem" IN(_datamodels) 
| where action="created" 
| where like(file_name, "%.doc%") OR like(file_name, "%.xls%") OR like(file_name, "%.ppt%") 
| stats count(file_name) AS count BY dest_user_id, dest_device_id, span(timestamp, 10m) 
| where count > 20 
| eval start_time=window_start, end_time=window_end, entities=mvappend(dest_user_id, dest_device_id), body=create_map(["count", count]) 
| into write_ssa_detected_events();

Associated Analytic Story

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 Filesytem node.

Required field

  • action
  • process
  • file_name
  • file_path

Kill Chain Phase

  • Exploitation

Known False Positives

user may copy a lot of office fies from one folder to another

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

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