Splunk unknown stable spl

Remote System Discovery with Adsisearcher

The following analytic detects the use of the `[Adsisearcher]` type accelerator in PowerShell scripts to query Active Directory for domain computers. It leverages PowerShell Script Block Logging (EventCode=4104) to identify specific script blocks containing `adsisearcher` and `objectcategory=computer` with methods like `findAll()` or `findOne()`. This activity is significant as it may indicate an attempt by adversaries or Red Teams to perform Active Directory discovery and gain situational awareness. If confirmed malicious, this could lead to further reconnaissance and potential lateral movement within the network.

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Detection Logic

`powershell` EventCode=4104 ScriptBlockText = "*adsisearcher*" 
AND ScriptBlockText = "*objectcategory=computer*" 
AND ScriptBlockText IN ("*findAll()*","*findOne()*")
| 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)`
| `remote_system_discovery_with_adsisearcher_filter`

False Positives

⚠ Administrators or power users may use Adsisearcher for troubleshooting.

Field Validations

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