Google ended up joined by Microsoft, Mozilla and Opera Software in a move to revoke rogue digital certificates issued by a subordinate certificate authority (CA) of France’s cybersecurity agency.
Google revoked the certificates for users of its Chrome browser on Saturday after a four-day investigation. Microsoft, Mozilla and Opera Software followed suit on Monday.
In a security advisory, Microsoft said it released an update to most versions of Windows — including Windows Phone 8, Windows 8.1 and Windows Server 2012 R2 — that revoked the pertinent certificates. Unlike other browser makers, Microsoft records trusted digital certificates in Windows, not in its Internet Explorer (IE) browser.
However, the third of Windows PC owners still running the 12-year-old Windows XP have been left out in the cold. “No update is available at this time for customers running Windows XP and Windows Server 2003,” Microsoft said in its advisory.
Google’s discovery also prompted Mozilla to annul the rogue certificates. The revocations will be a part of Firefox 26, which shipped Tuesday, Mozilla said.
Opera Software blacklisted the certificates in older versions of its Opera browser. The Norwegian company’s newest, Opera 12, did not require an update because that version did not automatically trust ANSSI (Agence nationale de la sécurité des systèmes d’information), the French Network and Information Security Agency whose intermediate CA issued the original unauthorized certificate.
According to ANSSI, DGTrésor, France’s Department of the Treasury, signed the certificates. ANSSI described the gaffe as “human error … during a process aimed at strengthening the overall IT security of the French Ministry of Finance.”
ANSSI found a secondary certificate ended up installed on a network monitoring device, and able to sniff local traffic to and from third-party sites, according to Google and Mozilla. Microsoft warned that, “An attacker could use these certificates to spoof content, perform phishing attacks, or perform man-in-the-middle attacks” against a large number of Google-owned domains, including google.com and youtube.com.