Recently, the certification authority DigiNotar has been compromised such that web sites certified by DigiNotar cannot be trusted anymore. This affects more than 500 prominent web sites incl. Google, Microsoft and others. An attacker might take advantage of this by intercepting encrypted web sessions.

Users are asked to update their system as soon as possible. Firefox installations on CERN Scientific Linux PCs and Internet Explorer installations on CERN centrally managed Windows PCs have already been updated. Users of Mozilla Firefox on Windows should install the latest updates from Mozilla. Users of any other system should update their system as soon as possible or delete/revoke the DigiNotar certificate from their web browser. Details can be found at: https://security.web.cern.ch/security/reports/en/announcements/HighRiskOfUnsafeWebBrowsing.shtml