Microsoft, Mozilla and Opera Software today joined Google in revoking rogue digital certificates that had been 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 had 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 included with Firefox 26, which is slated to ship on Tuesday, Mozilla said in a blog post today.
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, the certificates were signed by DGTrésor, France's Department of the Treasury. ANSSI described the gaffe as "human error ... during a process aimed at strengthening the overall IT security of the French Ministry of Finance."
According to Google and Mozilla, ANSSI found that a secondary certificate was installed on a network monitoring device, and able to sniff local traffic to and from third-party sites. 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.
The browser makers' fast response was in contrast to similar incidents in the past, when certificate invalidation took longer. An intermediate certificate issued by Turkish CA Turktrust in mid-2011 and installed on a firewall appliance in December 2012 was not revoked by Microsoft and others until early January 2013.
Like the ANSSI-backed rogue certificate, Turktrust's was able to spoof various Google domains.
In February 2012, another CA, Trustwave, admitted it had issued a certificate that allowed spying on SSL-secured traffic within a local network.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed . His email address is firstname.lastname@example.org.