Microsoft Exchange Server Buffer Overflow Vulnerability

Risk
High

Date Discovered
10-15-2003

Description
Microsoft has announced that Exchange Server is affected by a remotely exploitable buffer overflow condition. The overflow can be triggered remotely by unauthenticated SMTP clients. Microsoft has stated that remote code execution is possible on hosts running Exchange 2000 Server. Servers running Exchange Server 5.5 are vulnerable to a denial of service attack.

Symantec Vulnerability Assessment
Symantec Vulnerability Assessment detects and reports this vulnerability. Click here for the advisory released October 16, 2003.

Symantec Enterprise Security Manager
Symantec Enterprise Security Manager™ posted an update to the OS Patch Policy that detects and reports systems that are not patched against this vulnerability. Click here for the advisory released October 16, 2003.

Platforms Affected
Microsoft BackOffice 4.5
Microsoft Windows 2000 Advanced Server
Microsoft Windows 2000 Advanced Server SP1
Microsoft Windows 2000 Advanced Server SP2
Microsoft Windows 2000 Datacenter Server
Microsoft Windows 2000 Datacenter Server SP1
Microsoft Windows 2000 Datacenter Server SP2
Microsoft Windows 2000 Server
Microsoft Windows 2000 Server SP1
Microsoft Windows 2000 Server SP2
Microsoft Windows 2000 Workstation
Microsoft Windows 2000 Workstation SP1
Microsoft Windows 2000 Workstation SP2
Microsoft Windows NT 4.0
Microsoft Windows NT 4.0 SP1
Microsoft Windows NT 4.0 SP2
Microsoft Windows NT 4.0 SP3
Microsoft Windows NT 4.0 SP4
Microsoft Windows NT 4.0 SP5
Microsoft Windows NT 4.0 SP6
Microsoft Windows NT 4.0 SP6a

Components Affected
Microsoft Exchange Server 5.5 SP4
Microsoft Exchange Server 5.5 SP3
Microsoft Exchange Server 5.5 SP2
Microsoft Exchange Server 5.5 SP1
Microsoft Exchange Server 5.5
Microsoft Exchange Server 2000 SP3
Microsoft Exchange Server 2000 SP2
Microsoft Exchange Server 2000 SP1
Microsoft Exchange Server 2000

Recommendations
Block external access at the network boundary, unless service is required by external parties.
Access to internal SMTP servers should be blocked at the network border.

Disallow anonymous access to services. Permit access for trusted individuals only.
Implement SMTP authentication to prevent unauthenticated clients from attempting to use the service.

Deploy network intrusion detection systems to monitor network traffic for malicious activity.
Network intrusion detection systems may detect suspicious SMTP activity.

Patches are available:


Microsoft Exchange Server 5.5 SP4:

Microsoft Patch Security Update for Exchange 5.5 (KB829436)
http://www.microsoft.com/downloads/details.aspx?FamilyId=A9E872EA-54B0-4179-8AE9-5648BFB46459&displaylang=en

Microsoft Patch Security Update for Exchange 2000 (KB829436)
http://www.microsoft.com/downloads/details.aspx?FamilyId=7BAF5394-1B4E-4937-A570-9F232AE49F01&displaylang=en

References
Source: Microsoft Security Bulletin MS03-046
URL: http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulletin/MS03-046.asp

Credits
Credited to Joćo Gouveia.

Copyright (c) 2003 by Symantec Corp.
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Disclaimer
The information in the advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information.

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