name: Unusually Long Command Line
id: c77162d3-f93c-45cc-80c8-22f6a4264e7f
version: 5
date: '2020-12-08'
author: David Dorsey, Splunk
type: Anomaly
datamodel: []
description: Command lines that are extremely long may be indicative of malicious
  activity on your hosts.
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
  as lastTime FROM datamodel=Endpoint.Processes by Processes.user Processes.dest Processes.process_name
  Processes.process | `drop_dm_object_name("Processes")` | `security_content_ctime(firstTime)`|
  `security_content_ctime(lastTime)`|  eval processlen=len(process) | eventstats stdev(processlen)
  as stdev, avg(processlen) as avg by dest | stats max(processlen) as maxlen, values(stdev)
  as stdevperhost, values(avg) as avgperhost by dest, user, process_name, process
  | `unusually_long_command_line_filter` |eval threshold = 3 | where maxlen > ((threshold*stdevperhost)
  + avgperhost)'
how_to_implement: You must be ingesting endpoint data that tracks process activity,
  including parent-child relationships, from your endpoints to populate the Endpoint
  data model in the Processes node. The command-line arguments are mapped to the process
  field in the Endpoint data model.
known_false_positives: Some legitimate applications start with long command lines.
references: []
tags:
  analytic_story:
  - Suspicious Command-Line Executions
  - Unusual Processes
  - Possible Backdoor Activity Associated With MUDCARP Espionage Campaigns
  - Ransomware
  asset_type: Endpoint
  automated_detection_testing: passed
  cis20:
  - CIS 8
  confidence: 60
  context:
  - Source:Endpoint
  - Stage:Execution
  dataset:
  - https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1036.003/atomic_red_team/windows-sysmon.log
  impact: 70
  kill_chain_phases:
  - Actions on Objectives
  message: Unusually long command line $Processes.process_name$ on $dest$
  nist:
  - PR.PT
  - DE.CM
  observable:
  - name: dest
    type: Endpoint
    role:
    - Victim
  - name: Processes.process_name
    type: Process
    role:
    - Attacker
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  required_fields:
  - _time
  - Processes.user
  - Processes.dest
  - Processes.process_name
  - Processes.process
  risk_score: 42
  security_domain: endpoint