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  3. Microsoft Exchange Server Buffer Overflow Vulnerability

Microsoft Exchange Server Buffer Overflow Vulnerability

Risk

High

Date Discovered

October 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. The source of the issue appears to be in how the XEXCH50 verb is handled by the server. Microsoft has stated that remote code execution is possible on hosts running Exchange 2000 Server. Servers running Exchange Server 5.0 and 5.5 are vulnerable to a denial of service attack.

Technologies Affected

  • Microsoft Exchange Server 2000
  • Microsoft Exchange Server 2000 SP1
  • Microsoft Exchange Server 2000 SP2
  • Microsoft Exchange Server 2000 SP3
  • Microsoft Exchange Server 5.0
  • Microsoft Exchange Server 5.0 SP1
  • Microsoft Exchange Server 5.0 SP2
  • Microsoft Exchange Server 5.5
  • Microsoft Exchange Server 5.5 SP1
  • Microsoft Exchange Server 5.5 SP2
  • Microsoft Exchange Server 5.5 SP3
  • Microsoft Exchange Server 5.5 SP4

Recommendations

Block external access at the network boundary, unless external parties require service.

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 has released an update to thir advisory MS03-046 reporting the Exchange Server and related fixes. Please see the referenced advisory for more information and details on obtaining fixes.

Credits

Credited to João Gouveia.
Copyright © Symantec Corporation.
Permission to redistribute this alert electronically is granted as long as it is not edited in any way unless authorized by Symantec Security Response. Reprinting the whole or part of this alert in any medium other than electronically requires permission from secure@symantec.com.

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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