Marcel Boesch has reported a vulnerability in Mozilla and Firefox, which can be exploited by malicious people to cause a DoS (Denial of Service).
Arbitrary root certificates are imported silently without presenting users with a import dialog box when the MIME type is specified as: "application/x-x509-email-cert".
Due to another problem, this can e.g be exploited by malicious websites or HTML-based emails to prevent users from accessing valid SSL sites by placing invalid root certificates with the same DN (Distinguished Name) as a valid root certificate in a user's certificate store.
Successful exploitation prevents access to SSL-based sites that use a trusted root certificate with the same DN as a malicious root certificate in the user's certificate store.
The vulnerability has been reported in Mozilla 1.6, 1.7, and 1.7.1 for Windows and Linux, and in Mozilla Firefox 0.8 and 0.9.2. Other versions may also be affected.
Don't visit untrusted websites.
Check the certificate store and delete untrusted certificates if an error message is displayed with error code -8182 ("certificate presented by [domain] is invalid or corrupt") when attempting to access a SSL-based website.
"Edit" -> "Preferences" -> "Privacy & Security" -> "Certificates" -> "Manage Certificates..." -> "Authorities".
"Tools" -> "Options..." -> "Advanced" -> "Certificates" -> "Manage Certificates..." -> "Authorities".