HttpRequest with Certificate fails in Azure Web-role - azure

Question

On my deployed azure web-role I try to send a request (GET) to a Web-Server that authorizes the request by the provided certificate of the requesting client.
ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3;
var filepath = Path.GetTempPath();
string certpath = Path.Combine(filepath, "somecert.cer");
Trc.Information(string.Format("Certificate at {0} will be used", certpath));
X509Certificate cert = X509Certificate.CreateFromCertFile(certpath);
WebRequest request = WebRequest.Create(endPoint);
((HttpWebRequest)request).ProtocolVersion = HttpVersion.Version10;
((HttpWebRequest)request).IfModifiedSince = DateTime.Now;
((HttpWebRequest)request).AutomaticDecompression = DecompressionMethods.Deflate | DecompressionMethods.GZip;
((HttpWebRequest)request).ClientCertificates.Add(cert);
The above code works perfectly in the azure-emulator but not when it is deployed. Then the call to GetResponse fails always.
System.Net.WebException: The request was aborted: Could not create SSL/TLS secure channel.
at System.Net.HttpWebRequest.GetResponse()
at XYZ.Import.DataImport.OpenResponseStream(String endPoint)
I read through many of the existing discussion threads where using SecurityProtocolType.Ssl3 solved the problem but it does not in my case. Are there further debugging options considering that it is running on azure?
Update1
I tried all debugging steps that were suggested by Alexey. They are really helpfull but quite hard to execute properly on azure.
Here is with what I came up with after at least two hours.
I used the System.Net settings supplied by this post [1].
At first the output was not present in the expected folder. The file system settings on the folder need to be tweaked. Therefore the NT AUTHORITY\NETWORK SERVICE account should be allowed on the target folder.
After that the file didn't show up as expected because there seems to be a problem when only a app.config is supplied. See this thread [2]. So I provided a app.config a [ProjectAssembly].dll.config and a web.config with the content from the post [1].
To test if the Problem is related to User rights I tested with elevated rights and without like shown in post [3].
In advance I changed the Test-Project to execute in two modes. The first mode tries to load the public part in the *.cer file like shown in the code above.
The other version uses the private certificate that is loaded with this command
X509Certificate cert = new X509Certificate2(certpath, "MYPASSWORD", X509KeyStorageFlags.MachineKeySet);
As a result I gained the following insights.
When using the public part (.cer) it only works when the rights are elevated and the private cert is imported into the machine store
When using the private (.pfx) it only works if the private cert is imported into the machine store
The second setup with (.pfx) runs even without elevated rights
While debugging the CAPI2 log only had informations that had no direct relevance. The System.Net diagnostics from point one above contained this.
System.Net Information: 0 : [1756] SecureChannel#50346327 - Cannot find the certificate in either the LocalMachine store or the CurrentUser store.
[snip]
System.Net Error: 0 : [1756] Exception in HttpWebRequest#36963566:: - The request was aborted: Could not create SSL/TLS secure channel..
System.Net Error: 0 : [1756] Exception in HttpWebRequest#36963566::GetResponse - The request was aborted: Could not create SSL/TLS secure channel..
From this output and the changing situation when the elevated rights are used I would deduce that I should look further into the rights of the running web-role in combination with the certificate store.
[1] http://msdn.microsoft.com/de-de/library/ty48b824(v=vs.110).aspx
[2] Combined Azure web role and worker role project not seeing app.config when deployed
[3] http://blogs.msdn.com/b/farida/archive/2012/05/01/run-the-azure-worker-role-in-elevated-mode-to-register-httplistener.aspx

Answer 1

Remove SecurityProtocolType.Ssl3
Turn on CAPI2 log and check it for errors (on your local machine).
If there isn't error, then check location of CA and intermediate certificates.
Turn on system.net diagnostics and check this log for errors.
In this article describes how to find and turn on CAPI2 eventlog.
Hope this help.