splApache-2.0from splunk/security_content

Print Spooler Adding A Printer Driver

The following analytic detects the addition of new printer drivers by monitoring Windows PrintService operational logs, specifically EventCode 316. This detection leverages log data to identify messages indicating the addition or update of printer drivers, such as "kernelbase.dll" and "UNIDRV.DLL." This activity is significant as it may indicate exploitation attempts related to vulnerabilities like CVE-2021-34527 (PrintNightmare). If confirmed malicious, attackers could gain code execution or escalate privileges, potentially compromising the affected system. Immediate isolation and investigation of the endpoint are recommended.

Quality

FP risk

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Rule sourcedetections/endpoint/print_spooler_adding_a_printer_driver.yml

`printservice` EventCode=316 category = "Adding a printer driver" Message = "*kernelbase.dll,*" Message = "*UNIDRV.DLL,*" Message = "*.DLL.*"
  | stats  count min(_time) as firstTime max(_time) as lastTime
    BY OpCode EventCode ComputerName
       Message
  | `security_content_ctime(firstTime)`
  | `security_content_ctime(lastTime)`
  | `print_spooler_adding_a_printer_driver_filter`