MacOS Gatekeeper Bypass

Name:MacOS Gatekeeper Bypass
id:2c9346f3-bbeb-48ce-8411-fc13d09d83a5
version:3
date:None
author:Raven Tait, Splunk
status:production
type:Anomaly
Description:Detects known MacOS security bypass techniques that may be used to enable malicious code execution. Specifically monitors for attempts to remove the com.apple.quarantine attribute using xattr, or to disable Gatekeeper protections via spctl --master-disable, both of which can allow untrusted or malicious applications to execute without standard system safeguards.
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 = "*xattr*"
Processes.process = "*com.apple.quarantine*"
)
OR
(
Processes.process = "*spctl*"
Processes.process = "*master-disable*"
)

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_gatekeeper_bypass_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:Administrators or power users may need to disable Gatekeeper to install unsigned tools.
References:
  -https://osquery.readthedocs.io/en/stable/deployment/process-auditing/
  -https://ss64.com/mac/xattr.html
  -https://ss64.com/mac/spctl.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 Privilege Escalation', 'MacOS Post-Exploitation', 'MacOS Persistence Techniques']

asset_type:Endpoint

mitre_attack_id:['T1553.001']

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/T1553.001/osquery_gatekeeper/osquery.log
  source: osquery
  sourcetype: osquery:results
 test_type:'unit'
manual_test:None