Windows Winrs.exe Local Command Execution via localhost/loopback

Alerts on Winrs.exe processes running locally by targeting localhost/loopback in /r or /remote.

FreeReviewedSigma · High · v1

Product: windows
Category: process_creation
Author: Liran Ravich, Nasreddine Bencherchali (SigmaHQ), DRL 1.1
Published: 2025-10-22
Updated: 2026-07-30

ATT&CK techniques

Defense Evasion → Lateral Movement

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1218System Binary Proxy Execution
Cred Access
Discovery
Lateral Movement
- T1021.006Windows Remote Management
Collection
C2
Exfiltration
Impact

What it detects

This rule flags process creations of Winrs.exe when its command line targets localhost or loopback addresses (including 127.0.0.1 and ::1). Winrs is commonly used for remote management, so local execution with these parameters can indicate proxy execution behavior for stealth or movement. The detection relies on Windows process creation telemetry, specifically matching Winrs image and command-line arguments for /r or /remote values.

Reporting behind it

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Windows Winrs.exe Local Command Execution via localhost/loopback

Pivot detection · T1218 · 9 related

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

windows-winrs-exe-local-command-execution-via-localhost-loopback-bcfece3d

title: Windows Winrs.exe Local Command Execution via localhost/loopback
id: 2bca43d0-1e1a-4ed7-b770-a95e380e1aae
status: experimental
description: This rule flags process creations of Winrs.exe when its command line targets localhost or loopback addresses (including 127.0.0.1 and ::1). Winrs is commonly used for remote management, so local execution with these parameters can indicate proxy execution behavior for stealth or movement. The detection relies on Windows process creation telemetry, specifically matching Winrs image and command-line arguments for /r or /remote values.
references:
  - https://cardinalops.com/blog/living-off-winrm-abusing-complexity-in-remote-management/
  - https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/winrs
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_winrs_local_command_execution.yml
author: Liran Ravich, Nasreddine Bencherchali, Huntrule Team
date: 2025-10-22
tags:
  - attack.lateral-movement
  - attack.stealth
  - attack.t1021.006
  - attack.t1218
logsource:
  category: process_creation
  product: windows
detection:
  selection_img:
    - Image|endswith: \winrs.exe
    - OriginalFileName: winrs.exe
  selection_local_ip:
    CommandLine|contains|windash:
      - /r:localhost
      - /r:127.0.0.1
      - /r:[::1]
      - /remote:localhost
      - /remote:127.0.0.1
      - /remote:[::1]
  filter_main_remote:
    CommandLine|contains|windash:
      - "/r:"
      - "/remote:"
  condition: all of selection_* or (selection_img and not 1 of filter_main_*)
falsepositives:
  - Unlikely
level: high
license: DRL-1.1
related:
  - id: bcfece3d-56fe-4545-9931-3b8e92927db1
    type: derived

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