Windows OpenWith.exe launches a binary via /c

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

FreeUnreviewedSigmahighv1

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

title: Windows OpenWith.exe launches a binary via /c
id: 48c7e16a-ad26-4fc4-b6f8-419d4c44def7
status: test
description: This rule identifies executions of OpenWith.exe where the command line includes the '/c' switch, indicating it is being used to run another binary. Attackers can use living-off-the-land style binaries to perform execution with less obvious direct process spawning. The detection relies on Windows process creation telemetry, matching the OpenWith.exe image path ending 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

What it detects

This rule identifies executions of OpenWith.exe where the command line includes the '/c' switch, indicating it is being used to run another binary. Attackers can use living-off-the-land style binaries to perform execution with less obvious direct process spawning. The detection relies on Windows process creation telemetry, matching the OpenWith.exe image path ending and the presence of '/c' in the command line.

Known false positives

Unknown

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