HackTool - NetExec File Indicators — Sigma Rule

Rule metadata and linked tags

Author: Swachchhanda Shrawan Poudel (Nextron Systems). Source status: experimental; severity: high. Source dates: 2026-04-08 / not supplied.

{
  "product": "windows",
  "category": "file_event"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 654816e0d428cbc05197a4d053868a3bad25e268762f3fe34d048b0ec5b2be59

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: HackTool - NetExec File Indicators
id: efc21479-9e83-41da-8cf1-122e06ba8db3
status: experimental
description: |
    Detects file creation events indicating NetExec (nxc.exe) execution on the local machine.
    NetExec is a PyInstaller-bundled binary that extracts its embedded data files to a "_MEI<random>" directory
    under the Temp folder upon execution. Files dropped under the "\nxc\" sub-directory of that
    extraction path are unique to NetExec and serve as reliable on-disk indicators of execution.
    NetExec (formerly CrackMapExec) is a widely used post-exploitation and lateral movement tool used for
    Active Directory enumeration, credential harvesting, and remote code execution.
references:
    - https://github.com/Pennyw0rth/NetExec
    - https://www.netexec.wiki/
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2026-04-08
tags:
    - attack.execution
    - attack.lateral-movement
    - attack.discovery
    - attack.t1021.002
    - attack.t1059.005
logsource:
    product: windows
    category: file_event
detection:
    selection:
        - Image|contains: '\nxc-windows-latest\'
        - TargetFilename|contains|all:
              - '\Temp\_MEI'
              - '\nxc\data\'
    condition: selection
falsepositives:
    - Unknown
level: high
regression_tests_path: regression_data/rules/windows/file/file_event/file_event_win_hktl_netexec_file_indicators/info.yml

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://github.com/Pennyw0rth/NetExec
• https://www.netexec.wiki/