Windows OpenWith.exe Launches Another Binary via /c

Flags Windows OpenWith.exe executions that include '/c', indicating it launched another binary.

FreeReviewedSigma · High · v2

Product: windows
Category: process_creation
Author: Beyu Denis, oscd.community (rule), @harr0ey (idea) (SigmaHQ), DRL 1.1
Published: 2019-10-12
Updated: 2026-07-31

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 identifies process creation where an executable named OpenWith.exe is launched with a command line containing the '/c' parameter. Attackers can use this behavior to indirectly start another binary while blending into legitimate Windows functionality. The detection relies on Windows process creation telemetry, matching the process image ending with '\OpenWith.exe' and the presence of '/c' in the command line.

Reporting behind it

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Windows OpenWith.exe Launches Another Binary via /c

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-openwith-exe-launches-a-binary-via-c-cec8e918

title: Windows OpenWith.exe Launches Another Binary via /c
id: 48c7e16a-ad26-4fc4-b6f8-419d4c44def7
status: test
description: This rule identifies process creation where an executable named OpenWith.exe is launched with a command line containing the '/c' parameter. Attackers can use this behavior to indirectly start another binary while blending into legitimate Windows functionality. The detection relies on Windows process creation telemetry, matching the process image ending with '\OpenWith.exe' and the presence of '/c' in the command line.
references:
  - https://github.com/LOLBAS-Project/LOLBAS/blob/4db780e0f0b2e2bb8cb1fa13e09196da9b9f1834/yml/LOLUtilz/OSBinaries/Openwith.yml
  - https://twitter.com/harr0ey/status/991670870384021504
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_lolbin_openwith.yml
author: Beyu Denis, oscd.community (rule), @harr0ey (idea), Huntrule Team
date: 2019-10-12
modified: 2021-11-27
tags:
  - attack.stealth
  - attack.t1218
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|endswith: \OpenWith.exe
    CommandLine|contains: /c
  condition: selection
falsepositives:
  - Unknown
level: high
license: DRL-1.1
related:
  - id: cec8e918-30f7-4e2d-9bfa-a59cc97ae60f
    type: derived

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