detection.wiki

Detection rules › Sigma

DarkGate - Autoit3.EXE Execution Parameters

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

Detects execution of the legitimate Autoit3 utility from a suspicious parent process. AutoIt3.exe is used within the DarkGate infection chain to execute shellcode that performs process injection and connects to the DarkGate command-and-control server.

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1059 Command and Scripting Interpreter

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

title: DarkGate - Autoit3.EXE Execution Parameters
id: f8e9aa1c-14f2-4dbd-aa59-b98968ed650d
status: test
description: |
    Detects execution of the legitimate Autoit3 utility from a suspicious parent process. AutoIt3.exe is used within
    the DarkGate infection chain to execute shellcode that performs process injection and connects to the DarkGate
    command-and-control server.
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.execution
    - attack.t1059
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection_proc:
        - Image|endswith: '\Autoit3.exe'
        - OriginalFileName: 'AutoIt3.exe'
    selection_parent:
        ParentImage|endswith:
            - '\cmd.exe'
            - '\KeyScramblerLogon.exe'
            - '\msiexec.exe'
    filter_main_legit_autoit_location:
        Image|endswith:
            - ':\Program Files (x86)\AutoIt3\AutoIt3.exe'
            - ':\Program Files\AutoIt3\AutoIt3.exe'
    condition: all of selection_* and not 1 of filter_main_*
falsepositives:
    - Unlikely
level: high

Stages and Predicates

Stage 0: condition

all of selection_* and not 1 of filter_main_*

Stage 1: selection_proc

selection_proc:
    - Image|endswith: '\Autoit3.exe'
    - OriginalFileName: 'AutoIt3.exe'

Stage 2: selection_parent

selection_parent:
    ParentImage|endswith:
        - '\cmd.exe'
        - '\KeyScramblerLogon.exe'
        - '\msiexec.exe'

Stage 3: not filter_main_legit_autoit_location

filter_main_legit_autoit_location:
    Image|endswith:
        - ':\Program Files (x86)\AutoIt3\AutoIt3.exe'
        - ':\Program Files\AutoIt3\AutoIt3.exe'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
Imageends_with:\Program Files (x86)\AutoIt3\AutoIt3.exe
Imageends_with:\Program Files\AutoIt3\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)
OriginalFileNameeq
  • AutoIt3.exe corpus 2 (sigma 2)
ParentImageends_with
  • \KeyScramblerLogon.exe
  • \cmd.exe corpus 20 (sigma 20)
  • \msiexec.exe