Windows PsExec/PAExec Command-Line Flags Escalating to LOCAL SYSTEM

Flags in PsExec/PAExec command lines requesting LOCAL SYSTEM execution are matched via process creation command-line telemetry.

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windows-psexec-paexec-command-line-flags-escalating-to-local-system-8834e2f7

title: Windows PsExec/PAExec Command-Line Flags Escalating to LOCAL SYSTEM
id: e517f91d-3280-4c40-9d60-4efb39462d4f
related:
  - id: 207b0396-3689-42d9-8399-4222658efc99
    type: similar
  - id: 8834e2f7-6b4b-4f09-8906-d2276470ee23
    type: derived
status: test
description: This rule identifies Windows process creation where the command line contains PsExec or PAExec and includes specific flags that request execution under LOCAL SYSTEM (e.g., -s and -i combinations with cmd/pwsh/powershell). Attackers commonly use these utilities to run payloads with high privileges, enabling further local compromise and persistence. The detection relies on process creation telemetry and matches string patterns in the CommandLine field for both the utility name and the SYSTEM-enabling arguments.
references:
  - https://learn.microsoft.com/en-us/sysinternals/downloads/psexec
  - https://www.poweradmin.com/paexec/
  - https://www.fireeye.com/blog/threat-research/2020/10/kegtap-and-singlemalt-with-a-ransomware-chaser.html
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_sysinternals_psexec_paexec_escalate_system.yml
author: Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2021-11-23
modified: 2024-03-05
tags:
  - attack.resource-development
  - attack.t1587.001
logsource:
  category: process_creation
  product: windows
detection:
  selection_sys:
    CommandLine|contains|windash:
      - " -s cmd"
      - " -s -i cmd"
      - " -i -s cmd"
      - " -s pwsh"
      - " -s -i pwsh"
      - " -i -s pwsh"
      - " -s powershell"
      - " -s -i powershell"
      - " -i -s powershell"
  selection_other:
    CommandLine|contains:
      - psexec
      - paexec
      - accepteula
  condition: all of selection_*
falsepositives:
  - Admins that use PsExec or PAExec to escalate to the SYSTEM account for maintenance purposes (rare)
  - Users that debug Microsoft Intune issues using the commands mentioned in the official documentation; see https://learn.microsoft.com/en-us/mem/intune/apps/intune-management-extension
level: high
license: DRL-1.1

What it detects

This rule identifies Windows process creation where the command line contains PsExec or PAExec and includes specific flags that request execution under LOCAL SYSTEM (e.g., -s and -i combinations with cmd/pwsh/powershell). Attackers commonly use these utilities to run payloads with high privileges, enabling further local compromise and persistence. The detection relies on process creation telemetry and matches string patterns in the CommandLine field for both the utility name and the SYSTEM-enabling arguments.

Known false positives

Admins that use PsExec or PAExec to escalate to the SYSTEM account for maintenance purposes (rare)
Users that debug Microsoft Intune issues using the commands mentioned in the official documentation; see https://learn.microsoft.com/en-us/mem/intune/apps/intune-management-extension

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.