Is Firefox still safer than IE?

The popular Firefox browser received a security upgrade, known as version 1.0.4, when the Mozilla Foundation released the new code on May 11. This upgrade closes a security hole that could allow a hacker Web site to install software without a visitors’ knowledge or approval.

This is the fourth minor update to Firefox since the open-source browser’s 1.0 release on Nov. 9, 2004. That doesn’t seem like very many patches to me, compared with Firefox’s dominant competition, Microsoft’s Internet Explorer (IE), which is included in every copy of Windows. But I’ve heard a surprising amount of comment that Firefox might no longer be as secure as IE.

At Microsoft’s Windows Hardware Engineering Conference (WinHEC), held in Seattle April 25-27, for example, an IE product manager made this case explicitly. Firefox had had (at that time) “three major releases,” she said, while Internet Explorer 6.0 had had none. This statement was presented as though a lack of upgrades to IE was a benefit.

In fact, Microsoft has released at least 20 major security patches for Windows or Internet Explorer since November 2004. Most of these patches were rated “Critical,” Microsoft’s most severe security alert level.

The evidence I’ve seen so far indicates that Firefox remains much more secure than IE. But it’s worth our time to take a closer look.

IE users were exposed for 200 days in 2004

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Some remarkable statistics comparing the major Web browsers have been developed by Scanit NV, an international security firm with headquarters in Brussels, Belgium, and Dubai, United Arab Emirates.

The company painstakingly researched the dates when vulnerabilities were first discovered in various browsers, and the dates when the holes were subsequently patched.

The firm found that IE was wide open for a total of 200 days in 2004, or 54% of the year, to exploits that were “in the wild” on the Internet.

The Firefox browser and its older sibling Mozilla had no periods in 2004 when a security flaw went unpatched before exploits started circulating on the Net. With the latest 1.0.4 upgrade, Firefox has retained its “patch-before-hackers-can-strike” record so far in 2005, as well.

These statistics are so important to understanding the “attack surface” of the major browsers that we should break down this study into its individual findings:

IE suffered from unpatched security holes for 359 days in 2004. According to Scanit, there were only 7 days out of 366 in 2004 during which IE had no unpatched security holes. This means IE had no official patch available against well-publicized vulnerabilities for 98% of the year.

Attacks on IE weaknesses circulated “in the wild” for 200 of those days. Scanit records the first sighting of actual working hacker code on the Internet. In this way, the firm was able to determine how many days an IE user was exposed to possible harm. When Microsoft released a patch for an IE problem, Scanit “stopped the clock” on the period of vulnerability.

Mozilla and Firefox patched all vulnerabilities before hacker code circulated. Scanit found that the Mozilla family of browsers, which share the same code base, went only 26 days in 2004 during which a Windows user was using a browser with a known security hole. Another 30 days involved a weakness that was only in the Mac OS version. Scanit reports that each vulnerability was patched before exploits were running on the Web. This resulted in zero days when a Mozilla or Firefox user could have been infected.

The Opera browser also experienced no days during which unpatched holes faced actual exploits, but Scanit began keeping statistics on Opera only since September 2004.

To see Scanit’s visual timeline of these holes, exploits, and fixes, visit the firm’s Internet Explorer page. On that page, click “Next Page” to see the timelines for Mozilla, Firefox, and Opera.

Firefox fixes take days, IE takes months

From the record to date, the Mozilla/Firefox team has shown that new security discoveries typically result in a patch being released in only a week or so.

This was certainly true in the case of Firefox version 1.0.4. The primary security hole that was closed by that version was unexpectedly publicized by the French Security Incident Response Team (FrSIRT) on May 5. The Firefox patch was released only six days later. (The apparent discoverer of the flaw, the Greyhats Security Group, had been working responsibly with Firefox’s development team and criticized the leak.)

Perhaps the responsiveness of the Mozilla development group will shame Microsoft into fixing security holes much faster in the future. The situation has become so bad that eEye Digital Security, a respected consulting service, maintains an “upcoming advisories” page showing how much time Microsoft is allowing critical problems that are reported to the Redmond company to go uncorrected.

At present, eEye’s count reveals that three critical unpatched issues currently affect Microsoft’s products. None of these have gone unpatched longer than 60 days, the period after which eEye considers a patch to be “overdue.” But some critical, widely-known security holes went as long as six months in 2003 and 2004 without an official fix being made available by Microsoft.

Another security firm that tracks security holes in IE, Firefox, and many other applications is Secunia, based in Copenhagen, Denmark. As of today, Secunia reports that there are still 19 unpatched security flaws in IE, the most severe of which is rated “highly critical.” Firefox has only 4 unpatched flaws, all of which are rated “less critical” or “not critical,” the lowest severity rating. Opera has none.

Microsoft officials often excuse their tardiness in fixing security holes in IE by saying that the code is so complex that any fix has a high likelihood of breaking something else. Well, who integrated IE so tightly into the operating system that the browser is so delicate? It’s Microsoft’s own poor programming that causes much of the software giant’s very visible problems.

Microsoft employs some of the best software developers in the world. The company enjoys a cash reserve of $35 billion and is highly profitable. Yet a tiny company that builds open-source browser software is making the Redmond giant look foolish and incompetent in securing its products.

I have no particular attachment to the Mozilla Foundation or its products. If the foundation’s browser software was a threat to Windows users, I’d say so. At the present time, several serious unpatched holes are known to exist in IE, while few or none plague Firefox. This isn’t a religious issue, it’s just a fact.

The foundation announced two weeks ago that they’d surpassed 50 million downloads of the free Firefox browser. The application is largely responsible for knocking down IE from a 94% market share in May 2004 to 87% in April 2005, according to OneStat. That’s a remarkable accomplishment, considering that IE is free and comes preinstalled with Windows. Sites with a base of expert Windows users report much higher levels of Firefox usage.

How to keep Firefox upgraded

No matter how fast Firefox’s developers update it, it doesn’t do you any good unless you’ve got the browser configured to notify you of updates. This is a simple matter, but it’s worth making sure you have it right:

Enable update checking. In Firefox, click Tools, Options, Advanced. Ensure that the selection for Periodically check for updates is on, both for Firefox and for My Extensions and Themes. This is the default setting, so most Firefox users will automatically get notices of updates.

Check for upgrades manually, if desired. You should see a dialog box informing you of new updates as the Mozilla Foundation releases them. There’s a random delay, however, so every user doesn’t try to download a new version on the same day. To check whether there’s an update that applies to you, click the red up-arrow that’s in the upper-right toolbar of the Firefox menu area.

Download the latest version. If a dialog box tells you an update is available, close the window, then open Firefox’s download page. If you want a version other than Windows U.S. English, click the Other Systems and Languages link and select your preferred version. Download the executable file to a temporary area of your hard disk, then close all apps (including Firefox itself) and run the installer.

It’s no longer necessary or recommended that you uninstall Firefox before upgrading to a new version. A few glitches affected upgrades to versions 1.0.1 and 1.0.2, but this has been corrected since 1.0.3.

It’s unfortunate that hackers are so attracted to browsers as a way to take over users’ computers. But that’s where the money is, as bank robber Willie Sutton once said. We have to accept a certain amount of upgrading as the price of using complex Windows applications. But we can reduce the threat to ourselves and others by using browsers that have a proven record of rapid, responsible development.

I’d like to thank reader Terry Engles for his help researching this topic. To send us more information about the browser wars, or to send us a tip on any other subject, visit WindowsSecrets.com/contact. You’ll receive a gift certificate for a book, CD, or DVD of your choice if you send us a comment that we print.

Brian Livingston is editor of the Windows Secrets Newsletter and the coauthor of Windows 2000 Secrets, Windows Me Secrets, and eight other books.

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