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AUSCERT External Security Bulletin Redistribution
ESB-2002.106 -- Microsoft Security Bulletin MS02-012
Malformed Data Transfer Request can Cause Windows SMTP Service to Fail
28 February 2002
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AusCERT Security Bulletin Summary
---------------------------------
Product: SMTP service
Vendor: Microsoft
Operating System: Microsoft Windows 2000
Microsoft Windows XP Professional
Microsoft Exchange 2000
Impact: Denial of Service
Access Required: Remote
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Title: Malformed Data Transfer Request can Cause Windows SMTP
Service to Fail
Date: 27 February 2002
Software: Microsoft Windows 2000; Microsoft Windows XP Professional
Microsoft Exchange 2000
Impact: Denial of Service
Max Risk: Low
Bulletin: MS02-012
Microsoft encourages customers to review the Security Bulletin at:
http://www.microsoft.com/technet/security/bulletin/MS02-012.asp.
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Issue:
======
An SMTP service installs by default as part of Windows 2000 server
products. Exchange 2000, which can only be installed on Windows 2000,
uses the native Windows 2000 SMTP service rather than providing its
own. In addition, Windows 2000 and Windows XP workstation products
provide an SMTP service that is not installed by default. All of
these implementations contain a flaw that could enable denial of
service attacks to be mounted against the service.
The flaw involves how the service handles a particular type of SMTP
command used to transfer the data that constitutes an incoming
mail. By sending a malformed version of this command, an attacker
could cause the SMTP service to fail. This would have the effect
of disrupting mail services on the affected system, but would not
cause the operating system itself to fail.
Mitigating Factors:
====================
- Windows XP Home Edition does not provide an SMTP service, and
is not affected by the vulnerability.
- Windows 2000 Professional and Windows XP Professional do provide
an SMTP service, but it is not installed by default.
- Windows 2000 server products do install the SMTP service by
default. However, best practices recommend disabling any
unneeded services, and systems on which the SMTP service had been
disabled would not be at risk.
- Exchange 5.5, even if installed on a Windows 2000 server, is not
affected by the vulnerability.
- The result of an attack would be limited to disrupting the SMTP
service and, depending on the system configuration, potentially
IIS and other internet services as well. However, it would not
disrupt any other system functions.
- The vulnerability would not enable an attacker to gain any
privileges on the affected system or to access users' email or
data.
Risk Rating:
============
- Internet systems: Low
- Intranet systems: Low
- Client systems: Low
Patch Availability:
===================
- A patch is available to fix this vulnerability. Please read the
Security Bulletin at
http://www.microsoft.com/technet/security/bulletin/ms02-012.asp
for information on obtaining this patch.
Acknowledgment:
===============
- H D Moore (hdm@secureaustin.com)
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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.
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