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Detection rules › Sigma

DarkGate - Autoit3.EXE File Creation By Uncommon Process

Status
test
Severity
medium
Log source
product windows, category file_event
Author
Micah Babinski
Source
github.com/SigmaHQ/sigma

Detects the usage of curl.exe, KeyScramblerLogon, or other non-standard/suspicious processes used to create Autoit3.exe. This activity has been associated with DarkGate malware, which uses Autoit3.exe to execute shellcode that performs process injection and connects to the DarkGate command-and-control server. Curl, KeyScramblerLogon, and these other processes consitute non-standard and suspicious ways to retrieve the Autoit3 executable.

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1059 Command and Scripting Interpreter
Command & ControlT1105 Ingress Tool Transfer

Event coverage

ProviderEventTitle
SysmonEvent ID 11FileCreate

Rule body yaml

title: DarkGate - Autoit3.EXE File Creation By Uncommon Process
id: 1a433e1d-03d2-47a6-8063-ece992cf4e73
status: test
description: |
    Detects the usage of curl.exe, KeyScramblerLogon, or other non-standard/suspicious processes used to create Autoit3.exe.
    This activity has been associated with DarkGate malware, which uses Autoit3.exe to execute shellcode that performs
    process injection and connects to the DarkGate command-and-control server. Curl, KeyScramblerLogon, and these other
    processes consitute non-standard and suspicious ways to retrieve the Autoit3 executable.
references:
    - https://github.security.telekom.com/2023/08/darkgate-loader.html
    - https://www.kroll.com/en/insights/publications/cyber/microsoft-teams-used-as-initial-access-for-darkgate-malware
    - https://github.com/pr0xylife/DarkGate/tree/main
author: Micah Babinski
date: 2023-10-15
tags:
    - attack.command-and-control
    - attack.execution
    - attack.t1105
    - attack.t1059
    - detection.emerging-threats
logsource:
    category: file_event
    product: windows
detection:
    selection:
        Image|endswith:
            - '\Autoit3.exe'
            - '\curl.exe'
            - '\ExtExport.exe'
            - '\KeyScramblerLogon.exe'
            - '\wmprph.exe'
        TargetFilename|endswith: '\Autoit3.exe'
    condition: selection
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    Image|endswith:
        - '\Autoit3.exe'
        - '\curl.exe'
        - '\ExtExport.exe'
        - '\KeyScramblerLogon.exe'
        - '\wmprph.exe'
    TargetFilename|endswith: '\Autoit3.exe'

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.

FieldKindValues
Imageends_with
  • \Autoit3.exe corpus 3 (sigma 3)
  • \ExtExport.exe corpus 3 (sigma 3)
  • \KeyScramblerLogon.exe corpus 2 (sigma 2)
  • \curl.exe corpus 30 (sigma 30)
  • \wmprph.exe
TargetFilenameends_with
  • \Autoit3.exe corpus 2 (sigma 2)