.NET Reporting Certificate Validation Failed

PKI Tutorials - Herong's Tutorial Examples

∟.NET Programs Communicating with HTTPS Servers

∟.NET Reporting Certificate Validation Failed

This section provides a tutorial example on how to catch .NET execution exception to report the server certificate validation error.

Why my .NET program gives such a useless error message when it fails to verify the server certificate? The answer is that my .NET program has no exception handling.

To prove this answer, I revised my .NET C# program as shown below:

// WebReaderWithException.cs
// Copyright (c) 2011, HerongYang.com, All Rights Reserved.
using System;
using System.IO;
using System.Text;
using System.Net;
public class WebReaderWithException {
   public static void Main(string[] args) {
      try {
         string url = args[0];
         WebRequest req = WebRequest.Create(url);
         WebResponse res = req.GetResponse();
         StreamReader web 
            = new StreamReader(res.GetResponseStream(),Encoding.UTF8);
         string line;
         while ((line = web.ReadLine()) != null)
            Console.WriteLine(line);
      } catch (Exception e) {
         Console.WriteLine(e.ToString());
      }
   }
}

Run my new program to connect to https://login.yahoo.com:

C:\herong>\windows\Microsoft.NET\Framework\v4.0.30319\csc 
   WebReaderWithException.cs

Microsoft (R) Visual C# 2010 Compiler version 4.0.30319.1
Copyright (C) Microsoft Corporation. All rights reserved.

C:\herong>WebReaderWithException.exe https://login.yahoo.com

System.Net.WebException: The underlying connection was closed: 
Could not establish trust relationship for the SSL/TLS secure channel.
---> System.Security.Authentication.AuthenticationException: 
The remote certificate is invalid according to the validation 
procedure.

   at System.Net.Security.SslState.StartSendAuthResetSignal(Protoco...
   at System.Net.Security.SslState.CheckCompletionBeforeNextReceive...
   at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, I...
   at System.Net.Security.SslState.ProcessReceivedBlob(Byte[] buffe...
   at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, In...
   at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, ...
   at System.Net.Security.SslState.CheckCompletionBeforeNextReceive...
   at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, I...
   at System.Net.Security.SslState.ProcessReceivedBlob(Byte[] buffe...
   at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, In...
   at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, ...
   at System.Net.Security.SslState.CheckCompletionBeforeNextReceive...
   at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, I...
   at System.Net.Security.SslState.ProcessReceivedBlob(Byte[] buffe...
   at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, In...
   at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, ...
   at System.Net.Security.SslState.CheckCompletionBeforeNextReceive...
   at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, I...
   at System.Net.Security.SslState.ProcessReceivedBlob(Byte[] buffe...
   at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, In...
   at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, ...
   at System.Net.Security.SslState.CheckCompletionBeforeNextReceive...
   at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, I...
   at System.Net.Security.SslState.ForceAuthentication(Boolean rece...
   at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncR...
   at System.Net.TlsStream.CallProcessAuthentication(Object state) ...
   at System.Threading.ExecutionContext.Run(ExecutionContext execut...
   at System.Threading.ExecutionContext.Run(ExecutionContext execut...
   at System.Net.TlsStream.ProcessAuthentication(LazyAsyncResult re...
   at System.Net.TlsStream.Write(Byte[] buffer, Int32 offset, Int32...
   at System.Net.PooledStream.Write(Byte[] buffer, Int32 offset, In...
   at System.Net.ConnectStream.WriteHeaders(Boolean async)
   --- End of inner exception stack trace ---
   at System.Net.HttpWebRequest.GetResponse()
   at WebReaderWithException.Main(String[] args)

Cool. Now my .NET test program is reporting the actual exception message, which confirms that the remote server certificate validation failed with root CA certificates deleted from the trusted certificate store.

Last update: 2011.

Table of Contents

About This Book

Introduction of PKI (Public Key Infrastructure)

Introduction of HTTPS (Hypertext Transfer Protocol Secure)

Using HTTPS with Google Chrome

Using HTTPS with Mozilla Firefox

HTTPS with IE (Internet Explorer)

Perl Scripts Communicating with HTTPS Servers

PHP Scripts Communicating with HTTPS Servers

Java Programs Communicating with HTTPS Servers

Windows Certificate Stores and Console