I am trying out SignalR core and while using Signal R .NET Client and trying to a connect to a server with https i get
AuthenticationException: The remote certificate is invalid according
to the validation procedure.
The error is self explanatory but how do i get around this ?
I do want to accept self signed certs.
Searching over internet gave no conclusive answer and approaches as ServicePointManager.ServerCertificateValidationCallback no longer work and i suppose that is logical as they are not used in this case.
Thanks.
Related
I'm trying to change our code to send emails with MailKit since the old SMTPClient is obsolete.
We connect to our own server and don't need to authenticate. Here is the code:
Using client = New SmtpClient()
Dim values = SQL.EMAIL_SQL.GetSMTPInfo("MailHostOutsideNetwork")
client.Connect(values.Item1, values.Item2, Security.SecureSocketOptions.None)
client.Send(Message)
client.Disconnect(True)
End Using
I have it working and sending emails as long as I don't use TLS or SSL. When I try to use either of them, I get the exception:
An error occurred while attempting to establish an SSL or TLS connection.
The server's SSL certificate could not be validated for the following reasons:
- The server certificate has the following errors:
- A certificate chain processed, but terminated in a root certificate which is not trusted by the trust provider.
So, my first idea was to contact our IT department and ask about the certificates. They told me we've never had any certificates and most likely never will (some licensing bullshit).
The problem is they still want us to use TLS when sending emails and my boss says that there must be a way to do that (which I basically answered with... well yeah if we had our system and certificates in order. She was not vey happy lol).
So, now I'm here asking you if there is any way of doing that. Sending emails using TLS with no certificates. Any ideas?
As Jimi noted, you can set a ServerCertificateValidationCallback method.
If you read the above docs, it may help you devise a better solution than just to return true, but in the simplest case, setting it to a function that always returns true will work for your needs.
Based on the error message, it sounds like there is a certificate chain, it's just that the SMTP server is probably using a self-signed SSL certificate and/or a root certificate that was generated by your company instead of by an official SSL Certificate Authority and therefore the root certificate used by your SMTP server is not trusted by the system sending the emails.
You can also check out MailKit's default behavior here: https://github.com/jstedfast/MailKit/blob/master/MailKit/MailService.cs#L356
Basically, if the problem is just an untrusted root (what it sounds like your issue is), then it falls back on a hard-coded list of trusted mail server certificate details that it checks against:
var cn = certificate.GetNameInfo (X509NameType.SimpleName, false);
var fingerprint = certificate.Thumbprint;
var serial = certificate.SerialNumber;
var issuer = certificate.Issuer;
Obviously you won't know these strings off the top of your head, but if you write a custom function that prints this information out, you could then hard-code those values into a future version of the validation callback function and feel a little safer than just returning true ;-)
I'm have an application deployed to salesforce on the force.com platform,
which I'm trying to configure a 2 way SSL for.
I.e.
I want that for each request sent to from SF to my server, a client certificate will be sent.
I did the necessary configurations on SF for the certificate to be sent, but I'm still getting 403.7 from the server, which means: forbidden, client certificate required.
I installed wireshark on the server, captured traffic to see the 2 way ssl handshake, and I'm trying to find in the server hello message where it tells the client the trusted CAs from which a client certificate should correspond, but I'm having difficulties finding it.
I suspect that's why the client does not send the certificate.
Can anyone point me to where in the server hello I should look? Or perhaps in another packet capture?
Thanks in advance.
Client Key Exchange record:
Here, the server sends its Certificate Request message and the client sends its Certificate message in response, but that message contains 0 certificates.
Typically, this happens when the client was unable to select a client certificate to use. Either it's not configured properly to make use of any certificate, or it can't find one that is issued by one of the acceptable CAs.
Look at the Certificate Request packet and check its certificate_authorities list. This is a list of the CA Distinguished Names (DNs) that the server is willing to accept.
One way or another, the client will need to find a client certificate with which it can build a chain towards of those DNs. In the simplest case, a client certificate issued by such a DN is available. Otherwise, the client could have to build a chain from a client cert to such a DN, it would need to have the necessary intermediate CA certificates to do so. (How this is done depends on the client's configuration mechanisms.)
If intermediate CA certificates are necessary and not available on the client side, you may need to configure your server to accept them and advertise them in the Certificate Request too.
Added a screenshot of the handshake captures. can you please point me to where I should be looking? –
See packet #31. It contains the Certificate Request. Also packet #33 contains the certificate from the client, so the reason is not the client does not send the certificate, but instead that the server either does not like the certificate because the validation failed or because the certificate is not sufficient as authorization for the requested resource. You might get more information from the servers log.
Not sure if this will help anyone else, but for our case of this issue everything was working when running locally in Visual Studio and in IIS, but when deployed to a real server, we were hitting a certificate issue during 2-way SSL as described above and verified in Wireshark.
Anyway, on that server we have also have a .NET 4.7.2 Console application which was calling the same API and everything was working fine.
But, our .NET 4.7.2 web API calls were failing. It appears that when the same code was running inside IIS the cert was not available during the SSL negotiation. (although it loaded fine)
Our solution at this point was to modify the following call to include the 3rd parameter.
certificate = new X509Certificate2(certificatepath, Password, X509KeyStorageFlags.MachineKeySet);
By default X509Certificate2 uses the UserKeySet option, so perhaps the application pool user or another thread in IIS (?) was having trouble accessing the cert for the negotiation.
Here are a couple of the related pages that I found useful during my research:
https://paulstovell.com/x509certificate2/
https://github.com/dotnet/runtime/issues/23437
I have my WCF service running in HTTP. I want to make my service run in HTTPS. I did this in my local with self seigned certificate and its working fine. But I'm getting
"Could not establish trust relationship for the SSL/TLS secure channel with authority"
error when I deployed my code in QA environment and created Self signed certificate for the same. I found some solution to validate the certificate at client side (Link). But I'm looking for some solution to fix this from server side. I don't want to disturb the client.
I suspect the error reflect that the client does not recognize your self-signed certificate or the underlying certificate authority. As such, until the client adds the client certificate to their certificate store or otherwise trusts the certificate, the only way they will be able to access the service is via a validation workaround like the one reflected in the link you included.
In order to determine the underlying cause of the issue, you may want to enable WCF Tracing and review the exceptions (especially inner exceptions).
My team supports many WCF connections protected by mutual certificate authentication. We have noticed that the error top level error may not provide as much information as the inner exception. Just yesterday, I had a site with that exact error. When we looked in the trace file, we saw an inner exception revealing that the certificate had not been deployed to the certificate store in the proper location. A few days previously, the “could not establish trust relationship” error had an underlying inner exception that revealed the certificate had been revoked by the certificate authority.
Hope this helps.
Regards,
So, for an assignment I need to use GnuTLS and to start of, I followed the client and server examples in the documentation (http://www.gnutls.org/manual/gnutls.html) (client and server examples with X.509). Everything works fine till there.
However, I would like the server to authenticate the client (which, in the examples, does not by default). A little research has lead me to changing the flag GNUTLS_CERT in:
gnutls_certificate_server_set_request (mSession, GNUTLS_CERT_REQUEST);
I understand that this returns an error if the client does not provide a certificate that matches the server's trusted CA. However, is this enough to authenticate the client, or should there be more steps for authentication?
Thanks in advance.
The ColdFusion documentation is weak on how and when to use it. What does it do? How does one use it?
Update: it seems to be broken, as outlined in Washing Client Certs in ColdFusion with SOAP – Part 2.
problems with CFHTTP handling SSLv3 sessions
Client certificates are a bit of a pain because of the overhead involved in using it.
As Jura says, you'll need a target server that uses client certificates as a mechanism for authentication. This server side piece does not need to be CF-based. The web server (IIS, for example) would be set up to require this. This is part of the SSL/TLS protocol, not specific to any language at the application level.
You would use this if the server you are requesting a resource from requires client certificates. The administrator of that server would need to give you the client certificate and private key ahead of time. As mentioned by user349433, this is commonly a PKCS12 (.p12 or .pfx) file.
The server will validate that the client certificate is "trusted" and if it is, it will allow the TLS/SSL handshake to proceed, and CF will be able to write the HTTP request on top of it.
The use case today is to prevent man-in-the-middle attacks, but because of the overhead involved with certificate distribution, revokation, etc. it's not terribly common.
If you want to know more about it, check out TLS 1.1 specification:
https://www.rfc-editor.org/rfc/rfc4346
https://www.rfc-editor.org/rfc/rfc4346#section-7.4.6
You are using client certificate in case if the target server uses that mechanism for authentication. You'll need to obtain specific client certificate from the service provider in order to be able to connect to the service. It's been used for some internet banking applications back in days I believe. Not sure what is the use case today for it, may be distributed corporate networks where you need to connect to corporate server over internet in a highly secure manner?