Wednesday, November 26, 2003

Yet More Internet Explorer Vulnerabilities

I think the following says it all about Microsoft's commitment to "trustworthy computing":

Multiple vulnerabilities have been identified in Internet Explorer, which in combination can be exploited to compromise a user's system.

1) A redirection feature using the "mhtml:" URI handler can be exploited to bypass a security check in Internet Explorer, which normally blocks web pages in the "Internet" zone from parsing local files.

2) The above redirection feature can also be exploited to download and execute a malicious file on a user's system. Successful exploitation requires that script code can be executed in the "MyComputer" zone.

3) A cross-site scripting vulnerability can be exploited to execute script code in the security zone associated with another web page if it contains a subframe. This may potentially allow execution of script code in the "MyComputer" zone.

4) A variant of a fixed vulnerability can still be exploited to hijack a user's clicks and perform certain actions without the user's knowledge. [Typical MS nonsense isn't it? They treat the symptom, but don't bother to get down to addressing the underlying problem, leaving the way open for small variations on an old theme to cause new hassles.]


5) An error in the download functionality can be exploited to disclose a user's cache directory by supplying a "HTM" file extension and an invalid value in the "Content-Type:" header field. This issue does not affect all versions and may have been fixed by the latest patch for Internet Explorer.

The vulnerabilities have been reported in Internet Explorer 6.0. However, other versions may also be affected and have been added due to the criticality of these issues.

PoC exploits (Proof of Concept) are available. [In plain English: these are already live threats, and you can expect to see worms targeting these holes any day now.]

Disable Active Scripting. [Yeah right. Kill off half of the functionality on your favorite websites, and you get to enjoy the obnoxious "ActiveX is Disabled" warning for free! Talk about a non-starter.]

Use another product. [Darn good advice, I'd say. A lot better than futzing around with active scripting for "safe" vs "unsafe" sites.]

(emphases added)

Well then, what are you waiting for? Spare yourself a lot of future anxiety, and go get a decent browser.