Microsoft Security Bulletin (MS00-058)
Patch Available for "Specialized Header" Vulnerability
Originally posted: August 14, 2000
Microsoft has released a patch that eliminates a security
vulnerability in Internet Information Server that ships with
Microsoft(r) Windows 2000. Under certain conditions, the
vulnerability could cause a web server to send the source code of
certain types of web files to a visiting user.
Frequently asked questions regarding this vulnerability and the patch
can be found at
If an IIS server receives a file request that contains a specialized
header as well as one of several particular characters at the end,
the expected ISAPI extension processing may not occur. The result is
that the source code of the file would be sent to the browser.
It is important to note that normal security recommendations militate
strongly against ever including sensitive information in .ASP files
and, if these recommendations have been followed, there would be no
sensitive information to compromise. The specialized header at issue
here cannot be created via a standard Internet browser, so the
request would need to be created by an alternate method.
Affected Software Versions
- Microsoft Internet Information Server 5.0
Note: This vulnerability is eliminated by installing Windows 2000
Service Pack 1
We recommend that customers apply SP1 as the preferred option for
eliminating this vulnerability, as it has been fully regression
tested and includes fixes for additional issues.
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 MS00-058,
- Microsoft Knowledge Base article Q256888 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
August 14, 2000: Bulletin Created.
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