On 17/11/15 16:25, Peter Bowen wrote:
<snip>
- RFC5280 sections 7.2 and 7.3 do indeed talk about the need for dNSNames,
domainComponents, etc, to only contain ASCII data. However, your report
also flags Subject CNs with non-ASCII data - AFAICT, this is permitted by
both RFC5280 and the BRs. It is common practice to put the "xn--" ASCII
string in a dNSName and the UTF-8 string in the Subject CN.
I read 7.2 again and it clearly calls out as only applying to
domainComponent attributes. I'll rerun with allowance for hostnames
with u-labels in CNs.
Thanks.
- You wanted to check that "public CAs were following the CA/Browser Forum
baseline requirements" when issuing certs. However, some of the certs in
your report were issued before any of the browsers / audit regimes demanded
that public CAs be compliant with the BRs. Furthermore, some of the certs in
your report were issued before the BRs even existed.
Yes, I should have been clearer here. The correct description should
be "determining if the names in unexpired certificates follow the
current BRs". As you point out, the BRs have changed over time and
didn't even exist when some of these were issued. That is why I
included the not before date; those examining the list should
determine their cutoff date.
My concern is that many folks won't take the step of determining a
sensible cutoff date. (Incidentally, this is why we deliberately only
looked back at the past 1 year's worth of certs in the research we
published last week).
See how quickly even the esteemed Dr Gutmann seemed to be willing to
take your report at face value - "That's still pretty scary, nearly
50,000 names from a who's-who of commercial CAs". ;-)
- You wanted to check "server auth certificates issued by public CAs".
However, I see some Code Signing Certificates in your report.
I included all certificates that included the serverAuth EKU and all
those that had no EKU. Can you provide an example of a code signing
cert in the list so I can figure out why this test failed?
CT knows about 2 certs issued by "COMODO RSA Code Signing CA", and your
report flagged both of them, even though both certs contain the EKU
extension with just the Code Signing OID.
https://crt.sh/?Identity=%25&iCAID=2035
I'm pretty optimistic that all of the "anomalies" issued by Comodo's CA
system (except for the 8 mentioned in our recent incident report) will be
found to fall into these categories, although I haven't done an exhaustive
analysis yet. If there are any other "anomalies", they're a bit lost in the
noise at present!
I'll rerun the data in a few hours. I also will fix the encoding
issues; somehow the character encoding got messed up on import to
Google Sheets.
Great. I tried importing the list into postgres but I couldn't persuade
it to accept the invalid character encodings, so I gave up.
I will also add a field column to help identify where
in the certificates the issues are occurring. Hopefully these changes
will help remove the noise.
Definitely. Thanks!
Thanks,
Peter
--
Rob Stradling
Senior Research & Development Scientist
COMODO - Creating Trust Online
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