Name:GetCurrent User with PowerShell Script Block id:80879283-c30f-44f7-8471-d1381f6d437a version:4 date:2024-10-17 author:Mauricio Velazco, Splunk status:production type:Hunting Description:The following analytic detects the execution of the `GetCurrent` method from the WindowsIdentity .NET class using PowerShell Script Block Logging (EventCode=4104). This method identifies the current Windows user. The detection leverages PowerShell script block logs to identify when this method is called. This activity is significant because adversaries and Red Teams may use it to gain situational awareness and perform Active Directory discovery on compromised endpoints. If confirmed malicious, this could allow attackers to map out user accounts and potentially escalate privileges or move laterally within the network. Data_source:
-Powershell Script Block Logging 4104
search:`powershell` EventCode=4104 ScriptBlockText = "*[System.Security.Principal.WindowsIdentity]*" ScriptBlockText = "*GetCurrent()*" | stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer UserID | rename Computer as dest, UserID as user | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `getcurrent_user_with_powershell_script_block_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 or power users may use this PowerShell commandlet for troubleshooting. References: -https://attack.mitre.org/techniques/T1033/ -https://docs.microsoft.com/en-us/dotnet/api/system.security.principal.windowsidentity.getcurrent?view=net-6.0&viewFallbackFrom=net-5.0 drilldown_searches:
: tags: analytic_story: - 'Active Directory Discovery' asset_type:Endpoint confidence:50 impact:30 message:System user discovery on $dest$ by $user$ mitre_attack_id: - 'T1033' observable: name:'dest' type:'Endpoint' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'Path' - 'Message' - 'OpCode' - 'ComputerName' - 'User' - 'EventCode' risk_score:15 security_domain:endpoint
