Added in readme. Added in additional error detection and failure states.

RDPSign.ps1

@@ -1,27 +1,60 @@
-# ==============================================================================
+<#
-# SIGN RDP CONNECTION FILES YOU CREATE ON THE MACHINE USING A SELF-SIGNED CERTIFICATE TO SUPRESS APRIL 2026 RDP SECURITY UPDATE WARNINGS WHEN OPENING REMOTE DESKTOP FILES
+	April2026-RDPPopupBypass
-# https://learn.microsoft.com/en-us/windows-server/remote/remote-desktop-services/remotepc/understanding-security-warnings#:~:text=When%20an%20RDP%20file%20is,as%20the%20following%20image%20shows.
+	Copyright (c) 2026 ACO Services Inc.
-# https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26151
+	Developed by Tanner Van Teeffelen
-# NOTE!! THIS WILL NO LONGER SHOW THE "Remote Desktop Connection security warning" FOR ANY SIGNED FILES AND ENSURES THESE FILES CAN'T BE MODIFIED AFTER SIGNING WITHOUT INVALIDATING THE SIGNATURE, WHICH WILL MAKE THE WARNING REAPPAER
+	
-# NOTE!! ANY GPO THAT MODIFIES "Specify SHA1 thumbprints of certificates that represent trusted .rdp publishers" WILL OVERWRITE THE SETTINGS CREATED BY THIS SCRIPT CAUSING THE SIGNED RDP FILE TO SHOW A WARNING AGAIN
+	This project contains code derived from:
-# IF YOU ARE IMPLEMENTING A GPO SOLUTION KEEP THIS IN MIND OR TRY TO ENSURE THAT THE GPO COMMA APPENDS TO THE EXISTING VALUES OF THE KEY ALREADY EXISTS (NOT STANDARD BEHAVIOUR)
+	April-2026-security-update-Remote-Desktop-Conection-security-warning
-# "THE SCRIPT IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND..."
+	Copyright (c) IanVanLier
-# ==============================================================================
+	
+	Licensed under the MIT License
+#>
+
+Clear-Host
 
 Add-Type -AssemblyName System.Windows.Forms
 
+if (-NOT ([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole(` [Security.Principal.WindowsBuiltInRole] "Administrator")) {
+    Write-Host "Insufficient permissions to run this script. Please run this as an administrator.`n" -ForegroundColor Red
+    $HOST.UI.RawUI.ReadKey(“NoEcho,IncludeKeyDown”) | OUT-NULL
+    $HOST.UI.RawUI.Flushinputbuffer()
+    exit 1
+}
+
+Write-Host "-------------------------------------------" -ForegroundColor Blue
+Write-Host "|Developed by Tanner Van Teeffelen        |" -ForegroundColor Blue
+Write-Host "|Copyright ACO Services Inc. 2021         |" -ForegroundColor Blue
+Write-Host "|Based on MIT-licensed work by IanVanLier |" -ForegroundColor Blue
+Write-Host "-------------------------------------------`n" -ForegroundColor Blue
+
 # 1. Configuration
 $rdpFile
-$certSubjectName = "ACO"
+$certSubjectName
-$certSubject = "CN=$certSubjectName"
 
-$FileBrowser = New-Object System.Windows.Forms.OpenFileDialog
+$FileBrowser = New-Object System.Windows.Forms.OpenFileDialog
-$FileBrowser.Title = "Select an RDP file."
+$FileBrowser.Filter = "RDP Files (*.rdp)|*.rdp|All Files (*.*)|*.*"
-
+$FileBrowser.DefaultExt = "rdp"
-if ($FileBrowser.ShowDialog() -eq "OK") {
+$FileBrowser.Title = "Select an RDP file."
-    $rdpFile = $FileBrowser.FileName
+
+if ($FileBrowser.ShowDialog() -eq "OK") {
+    $rdpFile = $FileBrowser.FileName
+} else {
+	Write-Host "File browser dialog closed. Please try again and select an .rdp file." -ForegroundColor Red
+	$HOST.UI.RawUI.ReadKey(“NoEcho,IncludeKeyDown”) | OUT-NULL
+	$HOST.UI.RawUI.Flushinputbuffer()
+	exit 2
 }
 
+if ([IO.Path]::GetExtension($rdpFile) -ne ".rdp") {
+    Write-Host "Invalid file type. Please try again and select an .rdp file." -ForegroundColor Red
+	$HOST.UI.RawUI.ReadKey(“NoEcho,IncludeKeyDown”) | OUT-NULL
+	$HOST.UI.RawUI.Flushinputbuffer()
+    exit 3
+}
+
+$certSubjectName = Read-Host "Please type in your desired certificate subject name (e.g. 'CompanyNameIT-RDP')"
+$certSubject = "CN=$certSubjectName"
+
 # 2. Check for existing certificate
 Write-Host "Searching for existing certificate: $certSubjectName..." -ForegroundColor Cyan
 $existingCert = Get-ChildItem Cert:\LocalMachine\My | Where-Object { $_.Subject -eq $certSubject } | Select-Object -First 1

README.md

@@ -0,0 +1,40 @@
+# April 2026 RDP Popup Bypass
+
+## Copyright
+
+Copyright (c) ACO Services Inc. 2026  
+Developed by Tanner Van Teeffelen  
+Based on MIT-licensed work by Ian Van Lier  
+
+Original repository:  
+https://github.com/IanVanLier/April-2026-security-update-Remote-Desktop-Conection-security-warning-
+
+---
+
+## Instructions
+
+Run `RDPSign.bat` as Administrator.
+
+---
+
+## License (MIT)
+
+```
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+```