Original release date: April 11, 2002
Last revised: --
A complete revision history can be found at the end of this file.
* Microsoft IIS 4.0, 5.0, and 5.1
A variety of vulnerabilities exist in various versions of Microsoft
IIS. Some of these vulnerabilities may allow an intruder to execute
arbitrary code on vulnerable systems.
There are a variety of vulnerabilities in Microsoft IIS. Many of these
vulnerabilities are buffer overflows that could permit an intruder to
execute arbitrary code on vulnerable systems.
We strongly encourage all sites running IIS to read Microsoft's
advisory on these and other vulnerabilities and take appropriate
action as soon as practical. Microsoft's bulletin is available at
Additional information about these vulnerabilities is available at
VU#363715 CAN-2002-0071 Microsoft Internet Information Server (IIS)
vulnerable to heap overflow during processing of crafted
".htr" request by "ISM.DLL" ISAPI filter
VU#883091 CAN-2002-0074 Microsoft Internet Information Server (IIS)
contains cross-site scripting vulnerability in IIS Help
Files search facility
VU#886699 CAN-2002-0148 Microsoft Internet Information Server (IIS)
contains cross-site scripting vulnerability in HTTP error
VU#520707 CAN-2002-0075 Microsoft Internet Information Server (IIS)
contains cross-site scripting vulnerability in redirect
VU#412203 CAN-2002-0073 Microsoft Internet Information Server (IIS)
vulnerable to DoS via malformed FTP connection status
VU#454091 CAN-2002-0150 Microsoft Internet Information Server (IIS)
vulnerable to buffer overflow via inaccurate checking of
delimiters in HTTP header fields
VU#721963 CAN-2002-0149 Microsoft Internet Information Server (IIS)
buffer overflow in server-side includes (SSI) containing
long invalid file name
VU#521059 CAN-2002-0072 Microsoft Internet Information Server (IIS)
vulnerable to DoS when URL request exceeds maximum
VU#610291 CAN-2002-0079 Microsoft Internet Information Server (IIS)
buffer overflow in chunked encoding transfer mechanism
VU#669779 CAN-2002-0147 Microsoft Internet Information Server (IIS)
buffer overflow in chunked encoding transfer mechanism
For many of the vulnerabilities, an intruder could execute arbitrary
code with privileges that vary according to which version of IIS is
running. In general, IIS 4.0 permits an intruder to execute code with
complete administrative privileges, while IIS 5.0 and 5.1 permit an
intruder to execute code with the privileges of the IWAM_computername
Microsoft Corporation has released Microsoft Security Bulletin
MS02-018, which announces the availability of a cumulative patch to
address a variety of problems. We strongly encourage you to read this
bulletin and take the appropriate corrective measures. MS02-018 is
In addition to applying the patch, or until it can be applied, we
recommend the following actions:
* Use the IIS Lockdown tool and URLScan to eliminate or reduce the
impact of some of these vulnerabilites; they may also eliminate or
reduce other vulnerabilities that have not yet been discovered.
The IIS Lockdown tool can also be used to disable ASP if it's not
needed. More information about the IIS Lockdown tool and URLScan
can be found at
* As Microsoft has recommended for quite some time, disable the HTR
ISAPI extension unless it is absolutely required.
* Disable anonymous FTP unless it is required.
* Don't give login credentials on IIS servers to untrusted users.
Our thanks to Microsoft Corporation for the information contained in
their advisory. Additionally, our thanks go to the various individuals
and organizations whom Microsoft identified as discovering the
vulnerabilities, including eEye Digital Security
(http://www.eeye.com), Serge Mister of Entrust, Inc.
(http://www.entrust.com), Dave Aitel of @Stake
(http://www.atstake.com), Peter Grundl of KPMG, Joe Smith
(email@example.com) and zenomorph (firstname.lastname@example.org) of
http://www.cgisecurity.com, Keigo Yamazaki of the LAC SNS Team
(http://www.lac.co.jp/security/), and Thor Larholm of Jubii A/S.
Author: Shawn V. Hernan
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April 11, 2002: Initial release
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