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tub91's avatar
tub91
Icon for Cirrus rankCirrus
Oct 18, 2022
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Client Authentication with certificate on one URI only

Hello, I need your help figuring out how to troubleshoot a new implementation. We have a VIP exhibiting our service. The VIP has its own SSL client profile. Behind this VIP is an IIS which has 5 we...
application delivery
  • Kevin_Stewart's avatar
    Kevin_Stewart
    Oct 27, 2022

    Just to quickly follow up on this question, the answer depends on when. From an OSI perspective, by the time you've reached the HTTP uri, the TLS handshake is already done, so you really don't have any other option but to perform renegotiation. Since the client and BIG-IP have already established a TLS session (without cert auth), you basically have to tell the client to start a new TLS handshake, while you flip on the cert auth option. Even APM does this for things like On-Demand Cert Auth, that happen after initial TLS handshake and after the access policy has started.

    If you can get to the data you're looking for before the TLS handshake finishes, like looking at the SNI in the layer 4 TCP payload, then it would be possible to switch client SSL profiles (between auth and non-auth SSL profiles).

  • tub91's avatar
    tub91
    Icon for Cirrus rankCirrus
    Oct 21, 2022

    Hi mihaic 

    Thank you for your answer. However, we would like to avoid using SSL Renegotiation.

    Is there any way to do this through the APM?

    • Kevin_Stewart's avatar
      Kevin_Stewart
      Icon for Employee rankEmployee
      Oct 27, 2022

      Just to quickly follow up on this question, the answer depends on when. From an OSI perspective, by the time you've reached the HTTP uri, the TLS handshake is already done, so you really don't have any other option but to perform renegotiation. Since the client and BIG-IP have already established a TLS session (without cert auth), you basically have to tell the client to start a new TLS handshake, while you flip on the cert auth option. Even APM does this for things like On-Demand Cert Auth, that happen after initial TLS handshake and after the access policy has started.

      If you can get to the data you're looking for before the TLS handshake finishes, like looking at the SNI in the layer 4 TCP payload, then it would be possible to switch client SSL profiles (between auth and non-auth SSL profiles).

    • iaine's avatar
      iaine
      Icon for Nacreous rankNacreous
      Oct 25, 2022

      Do your clients support SNI? If so, you could have two SSL profiles attached to your VIP. The default one would for your 4 websites and the SNI one would be for your site that requires Client Cert auth and so would have this option set to require. The default SSL profile would have Client Cert set to Ignore

      You could do this via APM I guess - if the requested HTTP Host equals the 5th site then you could enable APM and insert an On Demand Client Cert object

      SNI - https://support.f5.com/csp/article/K13452