Microsoft on Thursday officially released Internet Explorer 8, calling it "the best solution for how people use the Web today."

It is, unfortunately for Microsoft, not the only solution for using the Web today.

Microsoft has been steadily losing market share to Firefox and Safari for the past few years. Internet Explorer 8 represents the company's bid to reverse that trend, but it faces stiff competition as Apple, Google, and Mozilla continue to develop their own browsers with an eye toward a future full of Web-based software and services.

Microsoft CEO Steve Ballmer touted IE8's speed, ease of use, and security, stating that it "provides protection that no other browser can match."

That protection turns out not to be good enough to guarantee security. On Wednesday, a security researcher identified as Nils used an undisclosed exploit to compromise Internet Explorer 8, running under Windows 7 on a Sony Vaio, at the CanSecWest security conference in Vancouver, British Columbia. He managed to hack Safari and Firefox, too. Only Google's Chrome remained unsullied.

If IE8, like the competition, isn't 100% safe, it's safer than its predecessors. Microsoft claims it blocks two to four times more malware attacks than other browsers. The company points to a report issued on Thursday by NSS Labs indicating that IE8 blocks 69% of malicious URLs, which is significantly better than Firefox 3.07 (30%), Safari 3 (24%), Chrome 1.0.154 (16%), Opera 9.64 (5%), or IE7 (4%).

"It became obvious as the results were tallied that Microsoft has made considerable achievements in adding protection from socially engineered malware into Internet Explorer v8 (SmartScreen)," the NSS report states. "With a protection rating of 69%, Microsoft IE8 was by far the best at protecting against socially engineered malware and adds an excellent layer of protection on top of other endpoint protection solutions. We were impressed by the stability of IE8 (RC1)."

Google didn't immediately respond to a request for comment.