Name:Windows Account Discovery With NetUser PreauthNotRequire id:cf056b65-44b2-4d32-9172-d6b6f081a376 version:3 date:2024-10-17 author:Teoderick Contreras, Splunk status:production type:Hunting Description:The following analytic detects the execution of the PowerView PowerShell cmdlet Get-NetUser with the -PreauthNotRequire parameter, leveraging Event ID 4104. This method identifies attempts to query Active Directory user accounts that do not require Kerberos preauthentication. Monitoring this activity is crucial as it can indicate reconnaissance efforts by an attacker to identify potentially vulnerable accounts. If confirmed malicious, this behavior could lead to further exploitation, such as unauthorized access or privilege escalation within the network. Data_source:
-Powershell Script Block Logging 4104
search:`powershell` EventCode=4104 ScriptBlockText = "*Get-NetUser*" ScriptBlockText = "*-PreauthNotRequire*" | rename Computer as dest, UserID as user | stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText dest user | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_account_discovery_with_netuser_preauthnotrequire_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://docs.splunk.com/Documentation/UBA/5.0.4.1/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.= known_false_positives:Administrators may leverage PowerView for legitimate purposes, filter as needed. References: -https://www.cisa.gov/news-events/cybersecurity-advisories/aa23-347a drilldown_searches:
: tags: analytic_story: - 'CISA AA23-347A' asset_type:Endpoint confidence:50 impact:30 message:A user dicovery using powerview commandlet Get-NetUser with PreauthNotRequire parameter on $dest$. mitre_attack_id: - 'T1087' observable: name:'dest' type:'Hostname' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' risk_score:15 required_fields: - '_time' - 'ScriptBlockText' - 'dest' - 'EventCode' - 'user' security_domain:endpoint
