sigmamediumHunting

File Decryption Using Gpg4win

Detects usage of Gpg4win to decrypt files

Detection Query

selection_metadata:
  - Image|endswith:
      - \gpg.exe
      - \gpg2.exe
  - Description: GnuPG’s OpenPGP tool
selection_cli:
  CommandLine|contains|all:
    - " -d "
    - passphrase
condition: all of selection_*

Author

Nasreddine Bencherchali (Nextron Systems)

Created

2023-08-09

Data Sources

windowsProcess Creation Events

Platforms

windows

References

Tags

attack.execution

Raw Content

title: File Decryption Using Gpg4win
id: 037dcd71-33a8-4392-bb01-293c94663e5a
status: test
description: Detects usage 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: Nasreddine Bencherchali (Nextron Systems)
date: 2023-08-09
tags:
    - attack.execution
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