MacOS Account Created

Name:MacOS Account Created
id:491004ae-694f-453e-b1e0-fc1e65daeea1
version:4
date:None
author:Raven Tait, Splunk
status:production
type:Anomaly
Description:The following analytic detects the creation of a new local user account on a MacOS system. It leverages osquery logs to identify this activity. Monitoring the creation of local accounts is crucial for a SOC as it can indicate unauthorized access or lateral movement within the network. If confirmed malicious, this activity could allow an attacker to establish persistence, escalate privileges, or gain unauthorized access to sensitive systems and data.
Data_source:

• -Osquery Results

search:| tstats `security_content_summariesonly`
count min(_time) as firstTime
max(_time) as lastTime
from datamodel=Endpoint.Processes where

(
Processes.process = "*sysadminctl*"
Processes.process = "*-addUser*"
)
OR
(
Processes.process = "*createhomedir*"
Processes.process = "*-u*"
)
OR
(
Processes.process = "*dseditgroup*"
Processes.process IN (
"*edit*",
"*-a*"
)
)
OR
(
Processes.process = "*dscl*"
Processes.process = "*-create*"
)

by Processes.dest Processes.original_file_name Processes.parent_process_id
Processes.process Processes.process_exec Processes.process_guid
Processes.process_hash Processes.process_id
Processes.process_current_directory Processes.process_name
Processes.process_path Processes.user Processes.user_id
Processes.vendor_product

| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `macos_account_created_filter`

how_to_implement:This detection uses osquery and endpoint security on MacOS. Follow the link in references, which describes how to setup process auditing in MacOS with endpoint security and osquery. Also the [TA-OSquery](https://splunkbase.splunk.com/app/8574) must be deployed across your indexers and universal forwarders in order to have the osquery data populate the data models.
known_false_positives:Creating new accounts after initial endpoint management should be rare in most environments. Investigate and tune as needed.
References:
  -https://osquery.readthedocs.io/en/stable/deployment/process-auditing/
  -https://ss64.com/mac/sysadminctl.html
  -https://ss64.com/mac/dseditgroup.html
  -https://ss64.com/mac/dscl.html
drilldown_searches:
 name:'View the detection results for - "$user$" and "$dest$"'
 search:'%original_detection_search% | search user = "$user$" dest = "$dest$"'
 earliest_offset:'$info_min_time$'
 latest_offset:'$info_max_time$'
 name:'View risk events for the last 7 days for - "$user$" and "$dest$"'
 search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
 earliest_offset:'7d'
 latest_offset:'0'
analytic_story:['MacOS Persistence Techniques']

asset_type:Endpoint

mitre_attack_id:['T1136']

product:['Splunk Enterprise', 'Splunk Enterprise Security', 'Splunk Cloud']

category:endpoint

security_domain:endpoint

tags:

tests:
 name:'True Positive Test'
 attack_data:
  data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1136/osquery_account_creation/osquery.log
  source: osquery
  sourcetype: osquery:results
 test_type:'unit'
manual_test:None