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Description

The following analytic detects the use of the 'delete' command in Splunk, which can be used to remove queried data. This detection leverages the Splunk Audit data model, specifically monitoring ad-hoc searches containing the 'delete' command by non-system users. This activity is significant because the 'delete' command is rarely used and can indicate potential data tampering or unauthorized data removal. If confirmed malicious, this activity could lead to the loss of critical log data, hindering incident investigations and compromising the integrity of the monitoring environment.

  • Type: Anomaly
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Splunk_Audit
  • Last Updated: 2024-05-21
  • Author: Michael Haag, Splunk
  • ID: 8d3d5d5e-ca43-42be-aa1f-bc64375f6b04

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1059 Command and Scripting Interpreter Execution
Kill Chain Phase
  • Installation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


1
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3
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7



| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Splunk_Audit.Search_Activity where Search_Activity.search IN ("*
| delete*") Search_Activity.search_type=adhoc Search_Activity.user!=splunk-system-user by Search_Activity.search Search_Activity.info Search_Activity.total_run_time Search_Activity.user Search_Activity.search_type 
| `drop_dm_object_name(Search_Activity)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `splunk_command_and_scripting_interpreter_delete_usage_filter`

Macros

The SPL above uses the following Macros:

:information_source: splunk_command_and_scripting_interpreter_delete_usage_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • Search_Activity.search
  • Search_Activity.info
  • Search_Activity.total_run_time
  • Search_Activity.user
  • Search_Activity.savedsearch_name
  • Search_Activity.search_type

How To Implement

To successfully implement this search acceleration is recommended against the Search_Activity datamodel that runs against the splunk _audit index. In addition, this analytic requires the Common Information Model App which includes the Splunk Audit Datamodel https://splunkbase.splunk.com/app/1621/.

Known False Positives

False positives may be present if this command is used as a common practice. Filter as needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
27.0 90 30 $user$ executed the 'delete' command, if this is unexpected it should be reviewed.

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

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

source | version: 2