399173 - Certificate Domain Mismatch, Subject Common Name vs. Subject Alt Name

Status: RESOLVED DUPLICATE of bug 238142

(Firefox :: General, defect)

Description

[Joern Bratzke]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.7) Gecko/20070914 Firefox/2.0.0.7
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.7) Gecko/20070914 Firefox/2.0.0.7

When visiting https://www.blackhat.com after accepting the untrusted Certificate a  Info Box pops up saying: 'Security Error: Domain Name Mismatch You have attempted to establish a connection with "www.blackhat.com". However, the security certificate presented belongs to "www.blackhat.com". [...]'
This is quite irritating, because "www.blackhat.com" and "www.blackhat.com" is the same domain name. After examining the certificate I found out that, the Subject Common Name of the certificate is set to: "www.blackhat.com", but the Subject Alt Name is set to "DNS:blackhat.com". As a result when going to "https://blackhat.com" this error box does not pop up.

So my assumption is, that when Firefox checks the domain name against the cert supplied values, it uses Subject Alt Name to check, but then displays the common  name, which causes this ErrorBox when going to "https://www.blackhat.com".



Reproducible: Always

Steps to Reproduce:
1. 
2.
3.

Comment 1

[Jesse Ruderman]

This looks a lot like bug 369112, which is marked as invalid.  (That doesn't make any sense to me, given the nonsense error message that's displayed.)