Firefox Drops Support for Windows XP
6.9.18 securityweek Safety

Effective this week, Windows XP is no longer supported by Firefox. More than four years after Microsoft stopped supporting the platform, Mozilla is making a similar move.

Last year, the organization said support for Windows XP was expected to be dropped by June 18, but the browser developer took a few more months to make that happen.

On Wednesday, Mozilla announced the release of Firefox 62 and also revealed that it updated Firefox ESR (Extended Support Release) to version 60.2. With these releases, Mozilla cut support for Firefox ESR 52, which was the last version of Firefox with Windows XP support.

“At the end of February 2016, XP users made up 12% of release Firefox. By the end of February 2017, XP users made up 8% of release Firefox. If this trend continued without much change after we switched XP users to ESR, XP Firefox users would presently amount to about 2% of release users,” Mozilla says.

While Firefox ESR 52 continues to be available for download, it no longer receives security patches, meaning that any vulnerability found in the browser will remain unpatched.

With Chrome no longer supporting the platform since version 49 and Internet Explorer 8, the browser most used as standard on the platform, getting no security updates for more than two years, Windows XP users are left with no major browser than could keep them safe from exploits while navigating the Internet.

Although still widely used in organizations, Windows XP is currently a nearly-17-year-old operating system that hasn’t received security patches for over four years (although Microsoft did release emergency fixes last year, to address Shadow Brokers-related bugs exploited in the global WannaCry outbreak).

“It required effort, and it required devoting resources to supporting XP well after Microsoft stopped doing so. It meant we couldn’t do other things, since we were busy with XP,” Mozilla says.

Users impacted by the recent change in Firefox are advised to upgrade to a newer operating system to continue receiving patches not only for Mozilla’s applications, but also for other software their computers depend on.

In addition to dropping support for XP, Firefox now includes a preference that allows users to distrust certificates issued by Symantec (by setting "security.pki.distrust_ca_policy" to 2 in about:config). This is yet another step towards removing all trust for Symantec-issued certificates in Firefox 63.

Firefox 62, Mozilla notes in an advisory, also addresses several vulnerabilities: 1 Critical severity, 3 High risk, 2 Medium severity, and 3 Low risk. Affecting Firefox 61 and Firefox ESR 60.1, the most important of these could potentially be exploited to run arbitrary code.