Windows File Share Discovery With Powerview

 Original Source: [splunk source]
Name:Windows File Share Discovery With Powerview
id:a44c0be1-d7ab-41e4-92fd-aa9af4fe232c
version:11
date:None
author:Mauricio Velazco, Splunk
status:production
type:TTP
Description:The following analytic detects the execution of the Invoke-ShareFinder PowerShell cmdlet from PowerView. This detection leverages PowerShell Script Block Logging to identify instances where this specific command is executed. Monitoring this activity is crucial as it indicates an attempt to enumerate network file shares, which may contain sensitive information such as backups, scripts, and credentials. If confirmed malicious, this activity could enable an attacker to escalate privileges or move laterally within the network, potentially compromising additional systems and sensitive data.
Data_source:
  • -Powershell Script Block Logging 4104
search:`powershell` EventCode=4104 (ScriptBlockText=Invoke-ShareFinder*)

| fillnull

| stats count min(_time) as firstTime max(_time) as lastTime
BY dest signature signature_id
user_id vendor_product EventID
Guid Opcode Name
Path ProcessID ScriptBlockId
ScriptBlockText

| `security_content_ctime(firstTime)`

| `security_content_ctime(lastTime)`

| `windows_file_share_discovery_with_powerview_filter`


how_to_implement:To successfully implement this analytic, you will need to enable PowerShell Script Block Logging on some or all endpoints. Additional setup here https://help.splunk.com/en/security-offerings/splunk-user-behavior-analytics/get-data-in/5.4.1/add-other-data-to-splunk-uba/configure-powershell-logging-to-see-powershell-anomalies-in-splunk-uba.=
known_false_positives:Security teams may leverage PowerView proactively to identify and remediate sensitive file shares. Filter as needed.
References:
  -https://github.com/PowerShellEmpire/PowerTools/blob/master/PowerView/powerview.ps1
  -https://thedfirreport.com/2023/01/23/sharefinder-how-threat-actors-discover-file-shares/
  -https://attack.mitre.org/techniques/T1135/
drilldown_searches:
 name:'View the detection results for - "$dest$" and "$user_id$"'
 search:'%original_detection_search% | search dest = "$dest$" user_id = "$user_id$"'
 earliest_offset:'$info_min_time$'
 latest_offset:'$info_max_time$'
 name:'View risk events for the last 7 days for - "$dest$" and "$user_id$"'
 search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$", "$user_id$") | 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:['Active Directory Privilege Escalation', 'Active Directory Discovery']

asset_type:Endpoint

mitre_attack_id:['T1135']

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/T1135/powerview_sharefinder/windows-powershell.log
  source: XmlWinEventLog:Microsoft-Windows-PowerShell/Operational
  sourcetype: XmlWinEventLog
 test_type:'unit'
manual_test:None