MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Execution | No specific technique |
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Sysmon | Event ID 1: Process creation |
Rule body
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
Stages and Predicates
Stage 0: condition
all of selection_*Stage 1: selection_metadata
selection_metadata:
- Image|endswith:
- '\gpg.exe'
- '\gpg2.exe'
- Description: 'GnuPG’s OpenPGP tool'
Stage 2: selection_cli
selection_cli:
CommandLine|contains|all:
- ' -d '
- 'passphrase'
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
CommandLine | match |
| field:"CommandLine" kind:match |
Description | eq |
| field:"Description" kind:eq value:"GnuPG’s OpenPGP tool" |
Image | ends_with |
| field:"Image" kind:ends_with |