Mutual certificates authentication fails with error 403.16

Question

I\'m using Windows Server 2012 and IIS 8.5. I\'ve set SSL for the website and the SSL Settings are: Require Required and Require Client Certificates.

The client cert

Answer 1

I have been working on this for a long time and finally found it!

Add a new key to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL Value name: ClientAuthTrustMode Value type: REG_DWORD Value data: 2

Refresh the webpage, select the certificate and watch the magic happen.

Research

Using Windows 8 and IIS 8.5 I followed the instructions here http://itq.nl/testing-with-client-certificate-authentication-in-a-development-environment-on-iis-8-5/.

Certificates were created in the correct place and everything configured in IIS properly but I kept getting 403.16 errors.

After the many MSDN articles and other attempts failed I found the following registry setting.

Set HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL Value name: ClientAuthTrustMode Value type: REG_DWORD Value data: 2

Set HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL Value name: SendTrustedIssuerList Value type: REG_DWORD Value data: 0 (False, or delete this key entirely)

Here is some more information about this specific setting (found here: http://technet.microsoft.com/en-us/library/hh831771.aspx)

Defaults for Trust Modes There are three Client Authentication Trust Modes supported by the Schannel provider. The trust mode controls how validation of the client’s certificate chain is performed and is a system-wide setting controlled by the REG_DWORD “ClientAuthTrustMode” under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel.

0 Machine Trust (default) Requires that the client certificate is issued by a certificate in the Trusted Issuers list.

1 Exclusive Root Trust Requires that a client certificate chains to a root certificate contained in the caller-specified trusted issuer store. The certificate must also be issued by an issuer in the Trusted Issuers list

2 Exclusive CA Trust Requires that a client certificate chain to either an intermediate CA certificate or root certificate in the caller-specified trusted issuer store. For information about authentication failures due to trusted issuers configuration issues, see Knowledge Base article 280256.

Hope this work for you as well.