Again a great “Security Now” podcast about SSL: how governments can sniff SSL traffic by enforcing Certificate Authorities to provide them with (intermediate CA) certificates. Based on this paper. Great story, recommended reading or listening!

Some things that I picked up:

  • Different CA’s can provide you with SSL certificate for same URL (or whatever)
  • Internet Explorer (actually the Windows crypto) downloads extra CA’s dynamically; so the list you see in IE can grow behind the scenes
  • Firefox manages the list of trusted CA’s itself
  • There is no standard policy for when a CA is accepted by browser vendors
  • The list of trusted CA’s should be based on your geographical location
  • Trusting a CA is somewhat equivalent to trusting a government
  • Browser should provide (advanced) users with extra features to help them decide if CA certificate should be trusted or not

In my daytime job, SSL/TLS is used a lot for communication between IT systems within the corporate firewall or with business partners across the Internet. Low level configuration of SSL/TLS is often not supported:

  • Configure single CA (or self-signed) cert to be trusted for specific outbound connection (e.g. when business partners have defined their “own CA”)
  • Different SSL client certificate per outbound connection
  • Easy configuration revocation checks (OCSP etc); and checking if the revocation checks actually work
  • Different timeout settings per connection
  • Only accept SSL connections on specific interfaces

Authored by: Guy