Forged SSL certificates for .google.com domain

Unknown managed to get a valid certificate for .google.com unauthorized. This makes it possible to conduct MITM attacks against users of Google services.
The certificate was issued by the Dutch certification authority DigiNotar and has now been withdrawn. Google Chrome
users are not in danger as it checks the validity of certificates online. Mozilla Firefox has released an update and recommend manually disabling the DigiNotar certificate in the browser settings. Microsoft has released a security bulletin and an update which removes the DigiNotar root certificate from the Microsoft Certificate Trust List. F-Secure Article