Background: CertStar issued certificates without verification
whatsoever. The faulty certs were signed with the PositiveSSL
certificate, which is chained to the UserTRUST root cert that Mozilla
ships. The UserTRUST cert is owned and operated by Comodo.
Our policy mandates that CAs have a valid audit to prove that they do
diligent verifications.
Thanks to Frank Hacker for posting the link to the what he thinks is the
latest audit of Comodo regarding normal certs (non-EV):
<https://cert.webtrust.org/SealFile?seal=798&file=pdf>
This audit is issued by KPMG. It merely certifies that Comodo follows
its *own* self-defined guidelines. (I think that is not sufficient, but
EV fixes that to some extend.)
The Comodo guidelines and processes, as certified by the above document,
are at
<http://www.comodo.com/repository/09_22_2006_Certification_Practice_Statement_v.3.0.pdf>
Section 1.10 shows that Comodo indeed uses Registration Authorities to
do all verification, see my previous post "Re: CAs and external entities
(resellers, outsourcing)"
<http://groups.google.com/group/mozilla.dev.tech.crypto/browse_thread/thread/43bdc908878eb4b4?q=#fd8d123e7881c729>
Most interesting to the current case, where the PositiveSSL certificate
proved most problematic and which was already contemplated to yank, is
section 2.4.1 a):
a) PositiveSSL Certificate
PositiveSSL Certificates are low assurance level Secure Server
Certificates from Comodo ideal for mail servers and server to server
communications. They are not intended to be used for websites
conducting e-commerce or transferring data of value.
...
Due to the increased validation speed and the nature of how Comodo intends
PositiveSSL certificates to be used, the certificates carry no warranty.
PositiveSSL certificates are available from the following channels:
Comodo Website, Reseller Network, Web Host Netowrk, PoweredSSL
Network, and EPKI Manager.
"not intended for ... e-commerce. ... the certificates carry no warranty"
It's clear that these certificates were never defined to be used in
browsers, and therefore never should have been shipped with browsers. In
any case, whatever Comodo's intends or actions, PositiveSSL does *not*
carry a valid audit for inclusion in browsers.
I think the fault is clearly on Codomo's side, as the PositiveSSL cert
is not included directly in Mozilla's root certs, but signed by Comodo's
UserTRUST cert, which is included in Mozilla browsers. Therefore, Comodo
is responsible for having allowed certificates for e-commerce which were
specifically excluded for e-commerce and which explicitly "carry no
warranty".
The audit was also faulty, because the signature of PositiveSSL by the
UserTRUST root and its inclusion in browsers is mentioned in the same
document in section 1.8.3. In other words, the document contradicts
itself and should never have been approved by the auditor (KPMG) as-is.
Suggested actions:
* Add PositiveSSL cert to cert root with trust bit disabled, i.e.
disabling it, assuming that works. IMHO, the current Firefox UI dialog
is fine. It's as if PositiveSSL were never added to the cert store,
which is what should have been the case all the time.
* Reconsider inclusion of Comodo certificates in the Mozilla root, as
Comodo has violated its own definitions.
* Require Comodo to remove the concept of Registration Authorities and
do all verifications themselves. At minimum, Comodo must do a Domain
Validation themselves.
* For KPMG having done a faulty audit, I don't know what the possible
actions are, legal or reputation nature.
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