Windows mpiexec.exe LOLBin: Flag combination with -n/n 1 for potential arbitrary execution

Alerts on Windows executions of mpiexec.exe with /n 1 or -n 1, correlated to a specific imphash, indicating LOLBin-style behavior.

FreeReviewedSigma · High · v2

Product: windows
Category: process_creation
Author: Florian Roth (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2022-01-11
Updated: 2026-07-31

Analysis Detection

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1218System Binary Proxy Execution
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags process creation events where mpiexec.exe is launched and the command line contains a specific -n or /n flag set to 1. This matters because certain mpiexec.exe usage patterns can be abused to launch other binaries, turning a legitimate HPC component into a proxy execution mechanism. The detection relies on Windows process creation telemetry, matching the process image ending in \mpiexec.exe and a particular imp-hash plus command-line substrings.

Reporting behind it

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Windows mpiexec.exe LOLBin: Flag combination with -n/n 1 for potential arbitrary execution

Pivot detection · T1218 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

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

windows-mpiexec-exe-lolbin-usage-with-n-1-n-1-flag-combination-729ce0ea

title: "Windows mpiexec.exe LOLBin: Flag combination with -n/n 1 for potential arbitrary execution"
id: b6f245a1-e180-4fd9-8b70-af3f21924769
status: test
description: This rule flags process creation events where mpiexec.exe is launched and the command line contains a specific -n or /n flag set to 1. This matters because certain mpiexec.exe usage patterns can be abused to launch other binaries, turning a legitimate HPC component into a proxy execution mechanism. The detection relies on Windows process creation telemetry, matching the process image ending in \mpiexec.exe and a particular imp-hash plus command-line substrings.
references:
  - https://twitter.com/mrd0x/status/1465058133303246867
  - https://learn.microsoft.com/en-us/powershell/high-performance-computing/mpiexec?view=hpc19-ps
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_lolbin_mpiexec.yml
author: Florian Roth (Nextron Systems), Huntrule Team
date: 2022-01-11
modified: 2024-11-23
tags:
  - attack.execution
  - attack.stealth
  - attack.t1218
logsource:
  category: process_creation
  product: windows
detection:
  selection_binary:
    - Image|endswith: \mpiexec.exe
    - Hashes|contains: IMPHASH=d8b52ef6aaa3a81501bdfff9dbb96217
  selection_flags:
    CommandLine|contains:
      - " /n 1 "
      - " -n 1 "
  condition: all of selection*
falsepositives:
  - Unknown
level: high
license: DRL-1.1
related:
  - id: 729ce0ea-5d8f-4769-9762-e35de441586d
    type: derived

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