Suspicious File Decryption Via Gpg4win (via process_creation)

title: Suspicious File Decryption Via Gpg4win (via process_creation)
id: 800b0fb0-cacd-5b52-ab41-bf6bdbd19527
status: stable
description: This rule detects use of Gpg4win to decrypt files
references:
    - https://blogs.vmware.com/security/2022/11/batloader-the-evasive-downloader-malware.html
    - https://www.gpg4win.de/documentation.html
    - https://news.sophos.com/en-us/2022/01/19/zloader-installs-remote-access-backdoors-and-delivers-cobalt-strike/
author: Huntrule Team
date: 2026-02-02
tags:
    - attack.execution
    - attack.defense-evasion
    - attack.t1140
logsource:
    category: process_creation
    product: windows
detection:
    selection_metadata:
        - Image|endswith:
              - '\gpg.exe'
              - '\gpg2.exe'
        - Description: 'GnuPG’s OpenPGP tool'
    selection_cli:
        CommandLine|contains|all:
            - ' -d '
            - 'passphrase'
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium