Name:Get ADUser with PowerShell Script Block id:21432e40-04f4-11ec-b7e6-acde48001122 version:4 date:2024-10-17 author:Teoderick Contreras, Mauricio Velazco, Splunk status:production type:Hunting Description:The following analytic detects the execution of the `Get-AdUser` PowerShell cmdlet, which is used to enumerate all domain users. It leverages PowerShell Script Block Logging (EventCode=4104) to identify instances where this command is executed with a filter. This activity is significant as it may indicate an attempt by adversaries or Red Teams to gather information about domain users for situational awareness and Active Directory discovery. If confirmed malicious, this behavior could lead to further reconnaissance and potential exploitation of user accounts within the domain. Data_source:
-Powershell Script Block Logging 4104
search:`powershell` EventCode=4104 ScriptBlockText = "*get-aduser*" ScriptBlockText = "*-filter*" | 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)` | `get_aduser_with_powershell_script_block_filter`
how_to_implement:The following Hunting analytic requires PowerShell operational logs to be imported. Modify the powershell macro as needed to match the sourcetype or add index. This analytic is specific to 4104, or PowerShell Script Block Logging. known_false_positives:Administrators or power users may use this command for troubleshooting. References: -https://www.blackhillsinfosec.com/red-blue-purple/ -https://attack.mitre.org/techniques/T1087/002/ -https://docs.microsoft.com/en-us/powershell/module/activedirectory/get-aduser?view=windowsserver2019-ps drilldown_searches:
: tags: analytic_story: - 'Active Directory Discovery' - 'CISA AA23-347A' asset_type:Endpoint confidence:50 impact:50 message:Powershell process having commandline "get-aduser" for user enumeration on $dest$ mitre_attack_id: - 'T1087.002' - 'T1087' observable: name:'dest' type:'Hostname' - role: - 'Victim' name:'user' type:'User' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'EventCode' - 'Message' - 'ComputerName' - 'User' risk_score:25 security_domain:endpoint
