Microsoft Security Bulletin (MS00-060)
Patch Available for "IIS Cross-Site Scripting" Vulnerabilities
Originally posted: August 25, 2000
Updated: November 2, 2000
On August 25, 2000, Microsoft released the original version of this
bulletin, to advise customers of the availability of a patch that
eliminates a vulnerability in Microsoft(r) Internet Information
Server. However, an additional variant of the vulnerability was
subsequently identified, and on November 2, 2000, the bulletin was
updated to advise customers of the availability of an updated patch.
The scope of the new vulnerability is exactly the same as that of the
originally-reported one. The updated patch eliminates all known
variants of the vulnerability. Customers who applied the original
version of the patch should apply the new version to ensure that they
are fully protected.
Frequently asked questions regarding this vulnerability and the patch
can be found at
On February 20, 2000, Microsoft and CERT published information on a
newly-identified security vulnerability affecting all web server
products. This vulnerability, known as Cross-Site Scripting (CSS),
results when web applications don't properly validate inputs before
using them in dynamic web pages. If a malicious web site operator
were able to lure a user to his site, and had identified a
third-party web site that was vulnerable to CSS, he could potentially
use the vulnerability to "inject" script into a web page created by
the other web site, which would then be delivered to the user. The
net effect would be to cause the malicious user's script to run on
the user's machine using the trust afforded the other site.
The vulnerability can affect any software that runs on a web server,
accepts user input, and blindly uses it to generate web pages.
Microsoft recommended that all vendors check their products to see if
any are affected by the vulnerability, and initiated a check of its
own products as well. Several features in IIS were found to be
affected - some were found by Microsoft internal teams, and others
were identified by customers - and this patch eliminates all of them.
Affected Software Versions
- Microsoft Internet Information Server 4.0
- Microsoft Internet Information Server 5.0
- Internet Information Server 4.0:
- Internet Information Server 5.0:
Note: Additional security patches are available at the Microsoft
Please see the following references for more information related to
- Frequently Asked Questions: Microsoft Security Bulletin MS00-060,
- Information on Cross-Site Scripting Security Vulnerability,
- CERT(r) Advisory CA-2000-02: Malicious HTML Tags Embedded in
Client Web Requests,
- Microsoft Knowledge Base article Q260347 discusses this issue and
will be available soon.
- Microsoft TechNet Security web site,
Obtaining Support on this Issue
This is a fully supported patch. Information on contacting Microsoft
Product Support Services is available at
Microsoft thanks Microsoft thanks Peter Grundl of Defcom
(www.defcom.com) for reporting the new variant of this issue to us
and working with us to protect customers.
- August 25, 2000: Bulletin Created.
- November 2, 2000: Bulletin updated to announce availability of a
patch to eliminate a new variant of this issue.
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Last Updated November 2, 2000