Lucene search

K
securityvulnsSecurityvulnsSECURITYVULNS:DOC:175
HistoryMay 11, 2000 - 12:00 a.m.

Security Bulletin (MS00-031)

2000-05-1100:00:00
vulners.com
86

The following is a Security Bulletin from the Microsoft Product Security
Notification Service.

Please do not reply to this message, as it was sent from an unattended
mailbox.
********************************

-----BEGIN PGP SIGNED MESSAGE-----

Microsoft Security Bulletin (MS00-031)


Patch Available for "Undelimited .HTR Request" and "File Fragment
Reading via .HTR" Vulnerabilities

Originally Posted: May 10, 2000

Summary

Microsoft has released a patch that eliminates two security
vulnerabilities in Microsoft(r) Internet Information Server. The
vulnerabilities could, respectively, be used to slow an affected web
server's response or to obtain the source code of certain types of
files under very restricted conditions.

Frequently asked questions regarding these vulnerabilities
and the patch can be found at
http://www.microsoft.com/technet/security/bulletin/fq00-031.asp

Issue

This patch eliminates two security vulnerabilities that are unrelated
except by virtue of the fact that both exist in the ISAPI extension
that provides web-based password administration via .HTR scripts.

  • The "Undelimited .HTR Request" vulnerability is a denial
    of service vulnerability. If a malicious user provided a
    password change request that was missing an expected
    delimiter, the algorithm would conduct an unbounded search.
    This would prevent it from servicing additional .HTR requests,
    and could also slow the overall response of the server.
  • The ".HTR File Fragment Reading" vulnerability could allow
    fragments of certain types of files to be read by providing a
    malformed request that would cause the .HTR processing to be
    applied to them. However, the vulnerability could only be
    exploited under extremely restrictive conditions, and the
    most valuable data in the files would be the least likely to
    actually appear in the fragments sent to the user.

Neither of these vulnerabilities would allow data to be added, deleted
or changed on the server, nor would they allow any administrative
control on the server to be usurped. Although .HTR files are used to
allow web-based password administration, neither of these
vulnerabilities involve any weakness in password handling. Also, if
security best practices have been followed, and unneeded script
mappings have been removed, many customers will have removed the .HTR
script mapping and thus be unaffected by either vulnerability.

Affected Software Versions

  • Internet Information Server 4.0
  • Internet Information Server 5.0

Patch Availability

Note: Additional security patches are available at the Microsoft
Download Center

More Information

Please see the following references for more information related to
this issue.

Obtaining Support on this Issue

This is a fully supported patch. Information on contacting Microsoft
Technical Support is available at
http://support.microsoft.com/support/contact/default.asp.

Acknowledgments

Microsoft thanks Internet Security Systems' X-force
(http://xforce.iss.net/), and David Litchfield of Cerberus Information
Security, Ltd (http://www.cerberus-infosec.co.uk/), for reporting
these vulnerabilities to us, and working with us to protect
customers.

Revisions

  • May 10, 2000: Bulletin Created.

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED
"AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL
WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES
WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL,
LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT
CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF
LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING
LIMITATION MAY NOT APPLY.

Last updated May 10, 2000

(c) 2000 Microsoft Corporation. All rights reserved. Terms of use.

-----BEGIN PGP SIGNATURE-----
Version: PGP 6.0.2

iQEVAwUBORoSp40ZSRQxA/UrAQGDqgf+JmL//1aDXlexAbRHL3mOu1N8dclUtP2y
XtB7fxhI4Xf579nR3ITbIBjJd5hfR3AlFnFA0zB5GK9PNn7HF25CAMBwE+8qo1rg
liVjSbzqgQja+5mibRwcRV7ez4E4BS1HVxs8e2kxxubb705lROHRvxxo/HyPWPum
QLJXgjd4Ukxorg2cCFU7rR/5cM6EnkvbRZfEjm+QgLDDYDRgoE4yerCIFYqrW9N6
RDnpHW2AmAkP7rRCn9Z6FPme9HzTAtvYyFq2e9u1G+il/EgJwjPShjqBRE9HkZfI
8Dmjfa7z41OzN/5meEOTeHg6puQB9ZingIFowxUweYgVcFAKdRfdmg==
=zUkE
-----END PGP SIGNATURE-----


You have received this e-mail bulletin as a result of your registration
to the Microsoft Product Security Notification Service. You may
unsubscribe from this e-mail notification service at any time by sending
an e-mail to [email protected]
The subject line and message body are not used in processing the request,
and can be anything you like.

To verify the digital signature on this bulletin, please download our PGP
key at http://www.microsoft.com/technet/security/notify.asp.

For more information on the Microsoft Security Notification Service
please visit http://www.microsoft.com/technet/security/notify.asp. For
security-related information about Microsoft products, please visit the
Microsoft Security Advisor web site at http://www.microsoft.com/security.