Try in Splunk Security Cloud

Description

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

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1204 User Execution Execution
T1204.002 Malicious File Execution
Kill Chain Phase
  • Actions on Objectives
NIST
  • ID.AM
  • PR.DS
CIS20
  • CIS 2
CVE
1
2
3
4
5
6
7
8
9
| 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`

Macros

The SPL above uses the following Macros:

:information_source: single_letter_process_on_endpoint_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
  • Processes.process_name

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.

Known False Positives

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

Associated Analytic Story

RBA

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

: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: 3