Windows Process: Notepad++ GUP (GUP.exe) Download Execution via -unzipTo and URL

Detects Notepad++ GUP.exe downloading over HTTP initiated by a non-Notepad++ parent process.

FreeReviewedSigma · High · v2
Product
windows
Category
process_creation
Author
Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published
2022-06-10
Updated
2026-07-31
title: "Windows Process: Notepad++ GUP (GUP.exe) Download Execution via -unzipTo and URL"
id: 5437f8bf-1e05-48da-9845-afac1fb5a1bb
status: test
description: This rule flags Windows process creation events where gup.exe (Notepad++ GUP utility) is launched and its command line includes both the -unzipTo argument and a URL containing http. It matters because gup is commonly used to retrieve content, and attackers may leverage legitimate tooling to download payloads or staging files. The detection relies on process creation telemetry, including Image/OriginalFileName and CommandLine fields, and it excludes cases where the parent process is notepad++.exe.
references:
  - https://twitter.com/nas_bench/status/1535322182863179776
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_gup_download.yml
author: Nasreddine Bencherchali (Nextron Systems), Huntrule Team
date: 2022-06-10
modified: 2023-03-02
tags:
  - attack.command-and-control
  - attack.t1105
logsource:
  category: process_creation
  product: windows
detection:
  selection_img:
    - Image|endswith: \GUP.exe
    - OriginalFileName: gup.exe
  selection_cli:
    CommandLine|contains|all:
      - " -unzipTo "
      - http
  filter:
    ParentImage|endswith: \notepad++.exe
  condition: all of selection* and not filter
falsepositives:
  - Other parent processes other than notepad++ using GUP that are not currently identified
level: high
license: DRL-1.1
related:
  - id: 44143844-0631-49ab-97a0-96387d6b2d7c
    type: derived