[cp-global] cryptoparty.in and SSL

[Kai Engert]

Here is another detail in the server side configuration of
cryptoparty.in, that might potentially cause problems:

The server is configured to return the root certificate in the TLS
handshake. Although it's OK and required to include all intermediate
certificates, the TLS server should exclude the root.

In this particular case, the certificate that should be removed from the
server configuration is:

Issuer: C=IL, O=StartCom Ltd., OU=Secure Digital Certificate Signing,
CN=StartCom Certification Authority
Subject: C=IL, O=StartCom Ltd., OU=Secure Digital Certificate Signing,
CN=StartCom Certification Authority
Serial Number: 1 (0x1)

In the NSS library used by Firefox and Chromium on Linux, this old root
certificate has been replaced with a newer one, which looks very
similar, has a "not before" date that is one second newer, uses a
stronger signature algorithm (SHA256) and has serial number 0x2d. [1]

Because both roots looks very similar, if the server sends it to the
browser, the browser verification logic might select it as the issuer.

Because the old root (serial 0x1) is no longer included in some modern
browsers as trusted, it might conclude the chain is untrusted.

This should be fixed in the server configuration, even though I'm not
sure it will fix the issue.

Kai

[1] https://bugzilla.mozilla.org/show_bug.cgi?id=602750