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Protection against international domain names, URL handling: Step 3

Trying to find out what's so special about IE7? Read up on the new security features present in IE7, and learn which of these features are user configurable.

Protection against international domain names

You could almost consider this security feature as an extension of the phishing filter except that it is automatically enabled and is used whether the phishing filter is in use or not. The idea is that oftentimes malicious Web sites try to impersonate well-known legitimate Web sites. One of the hardest things for a malicious Web site to impersonate is the legitimate site's URL. Less sophisticated perpetrators often rely on close misspellings of the legitimate site's URL. More sophisticated scam artists have begun using foreign language character sets in the URL. The idea is that some foreign language character sets use characters that are visually identical to characters used in the English alphabet, but they are not treated the same by the computer. This allows for the creation of a URL that looks identical to a legitimate URL.

To protect against this technique, Internet Explorer now notifies you when a URL contains a mix of character sets, since that often indicates that the site is malicious or misleading. Again, you don't have to do anything to enable this feature; it is enabled automatically.

URL handling

A feature that is similar to the foreign language filter is a new URL parser. In the past, attackers have embedded remote code execution commands in the URL. There are several different variations on this technique, but the most popular technique was one that included a command with an extremely long URL. The idea was that the URL's excessive length would cause a buffer overflow. If a command was positioned at just the right position within the URL, then the command could execute when the buffer overflow occurred.

That particular exploit was fixed long ago, but there are countless varieties of the technique that are still used today. IE7 contains a new URL parser that Microsoft designed to perform a sort of integrity check on URLs prior to unleashing them up on Internet Explorer.

The new URL parser is another example of a security feature that is enabled by default and is not configurable.

Configuring IE7 security on Vista

 Home: Introduction
 Step 1: General security configuration
 Step 2: Phishing filter
 Step 3: Protection against international domain names, URL handling
 Step 4: ActiveX opt-ins, information bar and cross-domain protection
 Step 5: Windows Vista and IE7

Brien M. Posey, MCSE, MVP
Brien M. Posey, MCSE, is a Microsoft Most Valuable Professional for his work with Windows 2000 Server and IIS. He has served as CIO for a nationwide chain of hospitals and was once in charge of IT security for Fort Knox. As a freelance technical writer, he has written for Microsoft, TechTarget, CNET, ZDNet, MSD2D, Relevant Technologies and other technology companies. You can visit his personal Web site at Copyright 2006 TechTarget

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