Browser Bugs Spare Internet Explorer for a Change

By Larry Seltzer  |  Posted 2005-02-07 Print this article Print

Reports surface on several browser bugs. Some affect Firefox only, while another allows address spoofing in every browser except IE.

A vulnerability that allows the URL in the browser address bar to be spoofed appears to affect all Web browsers apart from Internet Explorer.

The advisory announcing the vulnerability, which could facilitate phishing and other spoofing attacks, is related to IDN (International Domain Name) support in these browsers.

IDN allows for non-English lettering in domain names. It also allows for English lettering using non-English (unicode) character sets. Thus, in the proof-of-concept provided, when linked to "http://www.pа" the browsers display "". But the browsers handle it as "http://www.xn—"

The advisory lists as vulnerable the following browsers:
  • Most Mozilla-based browsers (Firefox 1.0, Camino .8.5, Mozilla 1.6, etc.)
  • Safari 1.2.5
  • Opera 7.54
  • OmniWeb 5

Separately, a researcher has revealed that three bugs—dubbed "Firedragging," "Firetabbing" and "Fireflashing" by their discoverer—bypass security mechanisms in Firefox 1.0. All three have been fixed in current Firefox builds, but not yet in a general release.

Firedragging allows an attacker to trick Firefox into placing an executable file on the Windows desktop. Normally, Firefox will only create a link to the file on the desktop. When presented with a hybrid file with GIF image data at the front and Windows batch file commands at the rear, Firefox will view the file as a GIF, no matter what its extension, and Windows will execute it as a batch file if it has a .BAT extension. The user still has to drag the file to the desktop and execute it from there.

Firetabbing bypasses security protections that prevent javascript: URLs from loading data in other windows when such a link is dropped on a tab in Firefox. According to the author, this can cause problems "from stealing session cookies to the ability to run arbitrary code on the client system, depending on the displayed site or security settings." Once again, the user must drop the link on a tab in order to invoke the problem.

Click here to read about high-risk flaws flagged in Internet Explorer and Mozilla. Fireflashing allows the contents of the about:config window, which displays Firefox configuration parameters, in a separate window or hidden frame. The user must double-click on a particular area of the display, for which they can be induced by a game or some other prompt, at which point parameters controlling the display of about:config may be changed, as long as the number of parameters is not changed.

Check out eWEEK.coms for the latest security news, reviews and analysis. And for insights on security coverage around the Web, take a look at Security Center Editor Larry Seltzers Weblog.
Larry Seltzer has been writing software for and English about computers ever since—,much to his own amazement—,he graduated from the University of Pennsylvania in 1983.

He was one of the authors of NPL and NPL-R, fourth-generation languages for microcomputers by the now-defunct DeskTop Software Corporation. (Larry is sad to find absolutely no hits on any of these +products on Google.) His work at Desktop Software included programming the UCSD p-System, a virtual machine-based operating system with portable binaries that pre-dated Java by more than 10 years.

For several years, he wrote corporate software for Mathematica Policy Research (they're still in business!) and Chase Econometrics (not so lucky) before being forcibly thrown into the consulting market. He bummed around the Philadelphia consulting and contract-programming scenes for a year or two before taking a job at NSTL (National Software Testing Labs) developing product tests and managing contract testing for the computer industry, governments and publication.

In 1991 Larry moved to Massachusetts to become Technical Director of PC Week Labs (now eWeek Labs). He moved within Ziff Davis to New York in 1994 to run testing at Windows Sources. In 1995, he became Technical Director for Internet product testing at PC Magazine and stayed there till 1998.

Since then, he has been writing for numerous other publications, including Fortune Small Business, Windows 2000 Magazine (now Windows and .NET Magazine), ZDNet and Sam Whitmore's Media Survey.

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