Description

Four vulnerabilities have been reported in IIS (Internet Information Server/Services), which can be exploited to conduct a Cross-Site Scripting attack, escalate privileges or cause a DoS (Denial of Service).

1) The vulnerability is caused due to an input validation error in the error pages generated, when a user is redirected. Specifically, the problem is that the ASP function, which handles the redirection, displays the URL in HTML without sanitising it.

A malicious person can exploit this to execute arbitrary script code in a user's browser session if the person is tricked into viewing a HTML document or click a malicious link. Successful exploitation can result in disclosure of various information (eg. cookie-based authentication information) associated with the referenced site or inclusion of malicious content, which the user thinks is part of the website.

2) The vulnerability is caused due to a boundary error when validating requests for Server-side include pages (eg. ".shtml", ".stm", and ".shtm"). Successful exploitation can allow a malicious user to execute arbitrary code on a vulnerable system but requires the ability to upload a Server-side include page.

The vulnerability only affects IIS 5.0.

3) The problem is that the ASP function "Response.AddHeader" doesn't set a limit on the size of a header returned to a web client. This can be exploited by a malicious user to cause a DoS by uploading a specially crafted ASP page, which generates an overly long header.

The vulnerability only affects IIS 4.0 and 5.0.

4) The vulnerability is caused due to an error in the way error conditions are handled when an overly long WebDAV request containing XML commands is received. A malicious person can exploit this to cause a DoS on a vulnerable system.

The vulnerability only affects IIS 5.0 and 5.1.

Solution
Apply patches.
Further details available in Customer Area

Original Advisory
http://www.microsoft.com/technet/security/bulletin/MS03-018.asp

Deep Links
Links available in Customer Area