The Firefox promotion site Spread Firefox was apparently hacked last weekend, on July 10, with the attackers potentially gaining access to the details of registered users, but more likely attempting to use the site to send spam,reports PC Pro.

A Mozilla Foundation senior staff member, Asa Dotzler, said in a statement on the site, "It appears that a part of Spread Firefox was hacked in an attempt to use it to send out spam. It does not look like the attacker accessed any personal data on the site, but to be safe, we're encouraging all of our users to log in and change their passwords."

Firefox remains the browser with the second-highest number of users according to reports from both Janco Associates and NetApplications, though Janco says interest in the new browser is waning (in part because of recent security issues) while NetApplications says Firefox is growing and approaching double-digit market share, ClickZ reports.

Firefox has 8.83 percent market share according to Janco, and NetApplications reports an 8.71 percent share.

The security breach was discovered July 12, and the site was taken down as a precautionary measure for several days before going live again on Friday, July 15, reports Information Week.

The intrusion is embarrassing for Firefox supporters, who claim the browser is more secure than Internet Explorer, writes WebPro News.