.net - Owin Twitter login - the remote certificate is invalid according to the validation procedure

Question

I started getting this error recently when trying to login using twitter- any idea why?

Stack Trace: 


[AuthenticationException: The remote certificate is invalid according to the validation procedure.]
   System.Net.TlsStream.EndWrite(IAsyncResult asyncResult) +230
   System.Net.PooledStream.EndWrite(IAsyncResult asyncResult) +13
   System.Net.ConnectStream.WriteHeadersCallback(IAsyncResult ar) +123

[WebException: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel.]
   System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult) +6432446
   System.Net.Http.HttpClientHandler.GetResponseCallback(IAsyncResult ar) +64

Answer 1

Thanks to the power of open source we can see that the thumbprints for the twitter certificates have been coded in the Katana Project.

Microsoft.Owin.Security.Twitter.TwitterAuthenticationOptions

Recently some certificates must have changed and now the thumbprints no longer match.

Please add a new thumb print for the "VeriSign Class 3 Public Primary Certification Authority - G5" Certificate to your Twitter Auth Options in your Startup.Auth.cs (for MVC users).

Change from the default:

app.UseTwitterAuthentication(
    consumerKey: "XXXX",
    consumerSecret: "XXX"
);

Use this:

app.UseTwitterAuthentication(new TwitterAuthenticationOptions
{
    ConsumerKey = "XXXX",
    ConsumerSecret = "XXXX",
    BackchannelCertificateValidator = new CertificateSubjectKeyIdentifierValidator(new[]
    {
        "A5EF0B11CEC04103A34A659048B21CE0572D7D47", // VeriSign Class 3 Secure Server CA - G2
        "0D445C165344C1827E1D20AB25F40163D8BE79A5", // VeriSign Class 3 Secure Server CA - G3
        "7FD365A7C2DDECBBF03009F34339FA02AF333133", // VeriSign Class 3 Public Primary Certification Authority - G5
        "39A55D933676616E73A761DFA16A7E59CDE66FAD", // Symantec Class 3 Secure Server CA - G4
        "5168FF90AF0207753CCCD9656462A212B859723B", //DigiCert SHA2 High Assurance Server C?A 
        "B13EC36903F8BF4701D498261A0802EF63642BC3" //DigiCert High Assurance EV Root CA
    })
});