Mozilla has been informed about the issuance of several fraudulent SSL certificates for public websites. The certificates have been revoked by their issuer which should protect most users. This is not a Firefox-specific issue. As part of our ongoing commitment to providing a secure Web experience for users, we have updated Firefox 4.0, 3.6, and 3.5 to recognize these certificates and block them automatically.
Impact to users
Users on a compromised network could be directed to sites using the fraudulent certificates and mistake them for the legitimate sites. This could deceive them into revealing personal information such as usernames and passwords. It may also deceive users into downloading malware if they believe it’s coming from a trusted site.
Current versions of Firefox are protected from this attack. We are still evaluating the possibility of further response to this issue. We encourage all users to keep their software up to date by regularly applying security updates.
This issue was reported to us by the Comodo Group, Inc., the certificate authority responsible for issuing the fraudulent certificates.