Potential Emotet Rundll32 Execution

title: Potential Emotet Rundll32 Execution
id: 54e57ce3-0672-46eb-a402-2c0948d5e3e9
status: test
description: Detecting Emotet DLL loading by looking for rundll32.exe processes with command lines ending in ,RunDLL or ,Control_RunDLL
references:
    - https://paste.cryptolaemus.com/emotet/2020/12/22/emotet-malware-IoCs_12-22-20.html
    - https://cyber.wtf/2021/11/15/guess-whos-back/
author: FPT.EagleEye
date: 2020-12-25
modified: 2023-02-21
tags:
    - attack.stealth
    - attack.t1218.011
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\rundll32.exe'
        - OriginalFileName: 'RUNDLL32.EXE'
    selection_cli:
        CommandLine|endswith:
            - ',RunDLL'
            - ',Control_RunDLL'
            # - ',#1'  too generic - function load by ordinal is not Emotet specific
    filter_legitimate_dll:
        CommandLine|endswith:
            - '.dll,Control_RunDLL'
            - '.dll",Control_RunDLL'
            - '.dll'',Control_RunDLL'
    filter_ide:
        ParentImage|endswith: '\tracker.exe' # When Visual Studio compile NodeJS program, it might use MSBuild to create tracker.exe and then, the tracker.exe fork rundll32.exe
    condition: all of selection_* and not 1 of filter_*
falsepositives:
    - Unknown
level: critical