The Mozilla Foundation said its open source Firefox browser passed the 50 million-download mark this week, less than a year after version 1.0 was released.

The alternative browser, which analytics firms claim has garnered anywhere from 6 percent to 10 percent of the gigantic browser market, has been building momentum since its launch last November.

The foundation seems to be chipping away at Microsoft (Quote, Chart) Internet Explorer's (IE) global stranglehold, mostly by boasting a more secure product at a time when Redmond's ubiquitous tool was being pounded by bugs, forcing the software giant to release reams of security alerts.

IE is estimated to have anywhere from 86 percent to 94 percent of the browser market, but analytics firms have squabbled over those numbers numerous times.

"It's funny how the counter just blows by 50 million without a care in the world, isn't it?" Mozilla developer Blake Ross wrote on Mozzila's Web site today. "But it's not just a number to us. It's a validation of half a decade of work, and the beginning of half a decade more."

However, the foundation says the 50 million is strictly version downloads and doesn't count upgrades.

Although the news might not be keeping Redmond executives awake at night, it is the first time in the nearly seven years since the software giant crushed former rival Netscape, that another browser has even appeared on the radar.

As previously reported by internetnews.com, Firefox, a descendent of the once popular Netscape browser, has had varying degrees of success. Originally named Firebird, the product went through several releases before its final launch.

Web-analytics firm OneStat.com says Firefox currently holds 8.69 percent of the global browser market, a 0.24 percent increase since February. Microsoft's IE has a global market share of 86.63 percent.

If the numbers bare out, and they are similar to OneStat.com's tally in February, it is the first time in several years that IE failed to capture at least 90 percent of Web users.

"It seems that people are switching from Microsoft's Internet Explorer to Mozilla's new Firefox browser," Niels Brinkman, co-founder of analytics firm One Stat.com, said in February. "The total usage share of Microsoft declined 5 percent, and the total usage share of Mozilla increased 5 percent."

While much of the interest in Firefox seems driven by security flaws found in IE, the upstart browser is now finding that with success comes the same security issues Microsoft has dealt with.

In January three flaws were discovered in the browser.

In other browser news, Opera Software said that version 8 of its browser has been downloaded two million times in the two weeks since its release.