MITM, almost: Redux

Apparently one of my OpenWRT boxes still uses OpenDNS. I was checking my Godaddy account then a Mozilla Firefox security error popped up. Note the https at the end of the host.


I didn't accept the certificate since I was already logged in. Unfortunately it didn't happen again so I was not able to verify. Was it a one time or erratic glitch? I'm not very sure who is at fault here, Godaddy or OpenDNS.

Somebody else experienced this and he asked Godaddy customer support. The CS response:

Thank you for contacting Online Support. We are sorry for any confusion with this process. You should be using the latest version of your web browser, as well as any new patches for these. We cannot control any errors that appear on browsers or any local security settings. However, the latest patches, web browser versions, etc. should rid these errors on your browsing.

Please let us know if we may be of further assistance.
Sincerely,
Ben P.
Online Support

The response was not satisfying to say the least but this is possibly a Mozilla Firefox bug. Replicating it is pretty hard so reporting will be a pain in the ass.