Windows HackTool Indicators: NetExec (nxc.exe) PyInstaller Extraction Artifacts

ATT&CK techniques

Execution → Lateral Movement

Recon
Resource Dev
Initial Access
Execution
- T1059.005Visual Basic
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
- T1021.002SMB/Windows Admin Shares
Collection
C2
Exfiltration
Impact

What it detects

This rule identifies Windows file creation events consistent with NetExec (nxc.exe) execution on a local host. It looks for a combination of execution-related content in the image path and on-disk PyInstaller extraction under the Temp directory, specifically including the extracted _MEI* folder and the nxc\data subdirectory. These extracted files are strong on-disk indicators because they are produced during NetExec startup as it unpacks embedded data to a temporary directory.

Reporting behind it

Related detections9 linkedT1059.005 — drag to rearrange

Suspicious Ransomware Fan-Out Deployment via PsExec Spread (Qilin)

Suspicious Impacket smbexec Command Execution Pattern

Suspicious Script Host Execution of Decoy-Named JavaScript Dropper (PS1Bot)

Malicious PathWiper Loader Script Execution from Windows Temp via WScript

Malicious Impacket Wmiexec Remote Command Execution Pattern

Suspicious Remote Admin Share Execution via Conhost

Suspicious Office Application Spawning Script Or Shell Interpreter

Malicious Script Host Spawning PowerShell With Invoke-Expression (via process_creation)

Suspicious MSHTA VBScript WScript Shell Execution

Windows HackTool Indicators: NetExec (nxc.exe) PyInstaller Extraction Artifacts

Pivot detection · T1059.005 · 9 related

Changelog

v2

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-netexec-execution-indicators-via-pyinstaller-mei-temp-file-drops-efc21479

title: "Windows HackTool Indicators: NetExec (nxc.exe) PyInstaller Extraction Artifacts"
id: ca3cb196-a3ec-4dc1-88b3-c8099e7a17d9
status: experimental
description: This rule identifies Windows file creation events consistent with NetExec (nxc.exe) execution on a local host. It looks for a combination of execution-related content in the image path and on-disk PyInstaller extraction under the Temp directory, specifically including the extracted _MEI* folder and the nxc\data subdirectory. These extracted files are strong on-disk indicators because they are produced during NetExec startup as it unpacks embedded data to a temporary directory.
references:
  - https://github.com/Pennyw0rth/NetExec
  - https://www.netexec.wiki/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/file/file_event/file_event_win_hktl_netexec_file_indicators.yml
author: Swachchhanda Shrawan Poudel (Nextron Systems), Huntrule Team
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
license: DRL-1.1
related:
  - id: efc21479-9e83-41da-8cf1-122e06ba8db3
    type: derived

Convert

This rule as a query you can run. Uses no unlock credit.

SplunkSPL