Potential Port Monitor or Print Processor Registration Abuseedit

Identifies port monitor and print processor registry modifications. Adversaries may abuse port monitor and print processors to run malicious DLLs during system boot that will be executed as SYSTEM for privilege escalation and/or persistence, if permissions allow writing a fully-qualified pathname for that DLL.

Rule type: eql

Rule indices:

  • logs-endpoint.events.*
  • endgame-*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100



  • Domain: Endpoint
  • OS: Windows
  • Use Case: Threat Detection
  • Tactic: Privilege Escalation
  • Data Source: Elastic Endgame
  • Data Source: Elastic Defend

Version: 105

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule queryedit

registry where host.os.type == "windows" and event.type in ("creation", "change") and
  registry.path : (
      "HKLM\\SYSTEM\\*ControlSet*\\Control\\Print\\Environments\\Windows*\\Print Processors\\*",
      "\\REGISTRY\\MACHINE\\SYSTEM\\*ControlSet*\\Control\\Print\\Environments\\Windows*\\Print Processors\\*"
  ) and registry.data.strings : "*.dll" and
  /* exclude SYSTEM SID - look for changes by non-SYSTEM user */
  not user.id : "S-1-5-18"