Disable Client Certificate Revocation (CRL) Check on IIS

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I have been asked this question on several occasions on how to disable revocation check in IIS 7.  It was pretty easy for IIS 6, on IIS 7 there is no documentation on how to do so. This post will describe on how to achieve this task.

Firstly, list out all the existing IIS bindings via command line as shown below:

netsh http show sslcert

Default SSL Binding when added via IIS Manager

IP:port                      : 0.0.0.0:443Certificate Hash             : 40db5bb1bf5659a155258d1d007c530fcb8996c2Application ID               : {4dc3e181-e14b-4a21-b022-59fc669b0914}Certificate Store Name       : MyVerify Client Certificate Revocation    : EnabledVerify Revocation Using Cached Client Certificate Only    : DisabledUsage Check                  : EnabledRevocation Freshness Time    : 0URL Retrieval Timeout        : 0Ctl Identifier               : (null)Ctl Store Name               : (null)DS Mapper Usage              : DisabledNegotiate Client Certificate : Disabled

NOTE:

  1. Client Certificate Revocation is always enabled by default.
  2. Application ID of “ {4dc3e181-e14b-4a21-b022-59fc669b0914} ” corresponds to IIS.

In order to disable the revocation check, we need to delete the existing binding first. Before you do that, make a note of the above details, especially the certificate hash.

NETSH command to delete existing SSL binding:

netsh http delete sslcert ipport=0.0.0.0:443

Now add the binding again using netsh as shown below:

NETSH command to add an SSL binding to disable CRL Check:

netsh http add sslcert ipport=0.0.0.0:443 certhash=40db5bb1bf5659a155258d1d007c530fcb8996c2appid={4dc3e181-e14b-4a21-b022-59fc669b0914}certstorename=My verifyclientcertrevocation=disable

 

Highlighted portion of the above command depicts that we are disabling the client certificate revocation. This adds a DWORD at the following location in registry:

REGISTRY  : HKLM\SYSTEM\CurrentControlSet\Services\HTTP\Parameters\SslBindingInfoDWORD    : DefaultSslCertCheckModeValue         : 1

DefaultSslCertCheckMode can take the following values. Click here for more info.

VALUE

MEANING
0 Enables the client certificate revocation check
1 Client certificate is not to be verified for revocation.
2 Only cached certificate revocation is to be used
4 The DefaultRevocationFreshnessTime setting is enabled
0x10000 No usage check is to be performed

 

Review the SSL bindings after executing the above command. The CRL check would be disabled.

netsh http show sslcert

SSL Binding added via NETSH to disable CRL:

IP:port                      : 0.0.0.0:443Certificate Hash             : 40db5bb1bf5659a155258d1d007c530fcb8996c2Application ID               : {4dc3e181-e14b-4a21-b022-59fc669b0914}Certificate Store Name       : MyVerify Client Certificate Revocation    : DisabledVerify Revocation Using Cached Client Certificate Only    : DisabledUsage Check                  : EnabledRevocation Freshness Time    : 0URL Retrieval Timeout        : 0Ctl Identifier               : (null)Ctl Store Name               : (null)DS Mapper Usage              : DisabledNegotiate Client Certificate : Disabled

NOTE: Client Certificate Revocation is always enabled by default.

More details on the netsh commands for HTTP can be found here: https://technet.microsoft.com/en-us/library/cc725882(v=ws.10).aspx#BKMK_2

MORE INFORMATION

NETSH Commands for HTTP in IIS 8:

With IIS there are 2 new SSL bindings viz. SNI Bindings and CCS Bindings. So the above commands would have to be modified slightly to incorporate these changes. So we have 2 additional parameters than what are listed in the above TechNet article . They are:

Tag

Value
hostnameport Unicode hostname and port for binding.
CCS Central Certificate Store binding.

hostnameport is very similar to the ipport. The only difference is that it takes a Unicode string as an input along with the port number.

Below are the modified commands for the corresponding bindings in IIS 8:

To delete a SNI Binding

netsh http delete sslcert hostnameport=www.sni.com:443

To delete a CCS Binding

netsh http delete sslcert ccs=443

To add a SNI Binding

netsh http add sslcert hostnameport=www.sni.com:443 certhash=40db5bb1bf5659a155258d1d007c530fcb8996c2 appid={4dc3e181-e14b-4a21-b022-59fc669b0914} certstorename=My verifyclientcertrevocation =disable

To add a CCS Binding

netsh http add sslcert ccs=443 appid={4dc3e181-e14b-4a21-b022-59fc669b0914} verifyclientcertrevocation =disable