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This search looks for process names that consist only of a single letter.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2020-12-08
  • Author: David Dorsey, Splunk
  • ID: a4214f0b-e01c-41bc-8cc4-d2b71e3056b4


ID Technique Tactic
T1204 User Execution Execution
T1204.002 Malicious File Execution

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes by Processes.dest, Processes.user, Processes.process, Processes.process_name 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(lastTime)` 
| `security_content_ctime(firstTime)` 
| eval process_name_length = len(process_name), endExe = if(substr(process_name, -4) == ".exe", 1, 0) 
| search process_name_length=5 AND endExe=1 
| table count, firstTime, lastTime, dest, user, process, process_name 
| `single_letter_process_on_endpoint_filter`

Associated Analytic Story

How To Implement

You must be ingesting data that records process activity from your hosts to populate the Endpoint data model in the Processes node. You must also be ingesting logs with both the process name and command line from your endpoints. The command-line arguments are mapped to the "process" field in the Endpoint data model.

Required field

  • _time
  • Processes.dest
  • Processes.user
  • Processes.process
  • Processes.process_name

Kill Chain Phase

  • Actions on Objectives

Known False Positives

Single-letter executables are not always malicious. Investigate this activity with your normal incident-response process.


Risk Score Impact Confidence Message
63.0 70 90 A suspicious process $process_name$ with single letter in host $dest$


Test Dataset

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

source | version: 3