name: Linux Doas Tool Execution
id: d5a62490-6e09-11ec-884e-acde48001122
version: 1
date: '2022-01-05'
author: Teoderick Contreras, Splunk
type: Anomaly
datamodel:
- Endpoint
description: This analytic is to detect the doas tool execution in linux host platform.
  This utility tool allow standard users to perform tasks as root, the same way sudo
  does. This tool is developed as a minimalistic alternative to sudo application.
  This tool can be abused advesaries, attacker or malware to gain elevated privileges
  to the targeted or compromised host. On the other hand this can also be executed
  by administrator for a certain task that needs admin rights. In this case filter
  is needed.
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
  as lastTime from datamodel=Endpoint.Processes where Processes.process_name = "doas"
  by Processes.dest Processes.user Processes.parent_process_name Processes.process_name
  Processes.process Processes.process_id Processes.parent_process_id Processes.process_guid
  | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
  | `linux_doas_tool_execution_filter`'
how_to_implement: To successfully implement this search, you need to be ingesting
  logs with the process name, parent process, and command-line executions from your
  endpoints. If you are using Sysmon, you can use the Add-on for Linux Sysmon from
  Splunkbase.
known_false_positives: Administrator or network operator can execute this command.
  Please update the filter macros to remove false positives.
references:
- https://wiki.gentoo.org/wiki/Doas
- https://www.makeuseof.com/how-to-install-and-use-doas/
tags:
  analytic_story:
  - Linux Privilege Escalation
  - Linux Persistence Techniques
  automated_detection_testing: passed
  cis20:
  - CIS 3
  - CIS 5
  - CIS 16
  confidence: 70
  context:
  - Source:Endpoint
  - Stage:Privilege Escalation
  - Stage:Persistence
  dataset:
  - https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1548.003/doas_exec/sysmon_linux.log
  impact: 70
  kill_chain_phases:
  - Exploitation
  message: A doas $process_name$ with commandline $process$ was executed on $dest$
  mitre_attack_id:
  - T1548.003
  - T1548
  nist:
  - DE.CM
  observable:
  - name: dest
    type: Hostname
    role:
    - Victim
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  required_fields:
  - _time
  - Processes.dest
  - Processes.user
  - Processes.parent_process_name
  - Processes.process_name
  - Processes.process
  - Processes.process_id
  - Processes.parent_process_id
  risk_score: 49
  security_domain: endpoint
  asset_type: Endpoint