Detection rules › Sigma
File Encryption/Decryption Via Gpg4win From Suspicious Locations
Detects usage of Gpg4win to encrypt/decrypt files located in potentially suspicious locations.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Execution | No specific technique |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 1 | Process creation |
Rule body yaml
title: File Encryption/Decryption Via Gpg4win From Suspicious Locations
id: e1e0b7d7-e10b-4ee4-ac49-a4bda05d320d
status: test
description: Detects usage of Gpg4win to encrypt/decrypt files located in potentially suspicious locations.
references:
- https://blogs.vmware.com/security/2022/11/batloader-the-evasive-downloader-malware.html
- https://news.sophos.com/en-us/2022/01/19/zloader-installs-remote-access-backdoors-and-delivers-cobalt-strike/
author: Nasreddine Bencherchali (Nextron Systems), X__Junior (Nextron Systems)
date: 2022-11-30
modified: 2023-08-09
tags:
- attack.execution
logsource:
category: process_creation
product: windows
detection:
selection_metadata:
- Image|endswith:
- '\gpg.exe'
- '\gpg2.exe'
- Product: 'GNU Privacy Guard (GnuPG)'
- Description: 'GnuPG’s OpenPGP tool'
selection_cli:
CommandLine|contains: '-passphrase'
selection_paths:
CommandLine|contains:
- ':\PerfLogs\'
- ':\Temp\'
- ':\Users\Public\'
- ':\Windows\Temp\'
- '\AppData\Local\Temp\'
- '\AppData\Roaming\'
condition: all of selection_*
falsepositives:
- Unknown
level: high
Stages and Predicates
Stage 0: condition
all of selection_*Stage 1: selection_metadata
selection_metadata:
- Image|endswith:
- '\gpg.exe'
- '\gpg2.exe'
- Product: 'GNU Privacy Guard (GnuPG)'
- Description: 'GnuPG’s OpenPGP tool'
Stage 2: selection_cli
selection_cli:
CommandLine|contains: '-passphrase'
Stage 3: selection_paths
selection_paths:
CommandLine|contains:
- ':\PerfLogs\'
- ':\Temp\'
- ':\Users\Public\'
- ':\Windows\Temp\'
- '\AppData\Local\Temp\'
- '\AppData\Roaming\'
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
CommandLine | match |
|
Description | eq |
|
Image | ends_with |
|
Product | eq |
|