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Description

The following analytic detects the occurrence of rare processes that appear only once across the network within a specified timeframe. It operates by compiling a list of process executions. This detection is crucial for a Security Operations Center (SOC) as it helps in identifying potentially malicious activities or unauthorized software that could indicate a security breach or an ongoing attack. Identifying such rare processes allows for early detection of threats, minimizing the potential impact of an attack which could range from data theft to complete system compromise.

  • Type: Anomaly
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2024-03-12
  • Author: Bhavin Patel, Splunk
  • ID: 44fddcb2-8d3b-454c-874e-7c6de5a4f7ac

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1204 User Execution Execution
Kill Chain Phase
  • Installation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


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| tstats `security_content_summariesonly` dc(Processes.dest) as dc_dest values(Processes.dest) as dest values(Processes.user) as user min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes by Processes.process_name 
| `drop_dm_object_name(Processes)` 
| search dc_dest < 10 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `detect_rare_executables_filter`

Macros

The SPL above uses the following Macros:

:information_source: detect_rare_executables_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
  • Processes.dest
  • Processes.user
  • Processes.process_name

How To Implement

The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.

Known False Positives

Some legitimate processes may be only rarely executed in your environment.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
25.0 50 50 A rare process - [$process_name$] has been detected on less than 10 hosts in your environment.

: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: 4