Microsoft Exchange Server 2000 IMAP Literal Processing DoS Vulnerability iDefense Security Advisory 05.08.07 http://labs.idefense.com/intelligence/vulnerabilities/ May 08, 2007 I. BACKGROUND Microsoft Exchange Server 2000 is a messaging product developed by Microsoft, part of the Windows Server System line of server products. More information about it can be found at the following URL. http://www.microsoft.com/technet/prodtechnol/exchange/2000/default.mspx II. DESCRIPTION Remote exploitation of an integer overflow vulnerability in the IMAP service of Microsoft Exchange 2000 could allow a remote attacker to crash all running Exchange services and other services in the same process. The vulnerability specifically exists in code responsible for reading of literals in the IMAP4 service. When the IMAP4 service encounters a specially crafted literal, it fails to properly process it. An access violation occurs causing an unhandled exception that terminates the process. III. ANALYSIS Exploitation of this vulnerability allows an attacker to cause the affected server to restart or potentially require data to be reinstalled from backup. As the Exchange server may run in the same process space as many other servers, crashing the IMAP4 component will also cause the SMTP, POP3, WWW and FTP services, if enabled, to exit. In order to exploit this vulnerability, the attacker must have access to establish a TCP session with the IMAP4 service. IV. DETECTION iDefense confirmed the existence of this vulnerability in Microsoft Exchange 2000 with Service Pack 3. V. WORKAROUND iDefense is not currently aware of any effective workarounds for this vulnerability. Consider applying network access controls on this service. VI. VENDOR RESPONSE Microsoft has addressed this vulnerability within MS07-026. For more information, consult their bulletin at the following URL. http://www.microsoft.com/technet/security/Bulletin/MS07-026.mspx VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2007-0221 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org/), which standardizes names for security problems. VIII. DISCLOSURE TIMELINE 01/10/2007 Initial vendor notification 01/22/2007 Initial vendor response 05/08/2007 Coordinated public disclosure IX. CREDIT This vulnerability was reported to iDefense by Joxean Koret. Get paid for vulnerability research http://labs.idefense.com/methodology/vulnerability/vcp.php Free tools, research and upcoming events http://labs.idefense.com/ X. LEGAL NOTICES Copyright © 2007 iDefense, Inc. Permission is granted for the redistribution of this alert electronically. It may not be edited in any way without the express written consent of iDefense. If you wish to reprint the whole or any part of this alert in any other medium other than electronically, please e-mail customerservice@private for permission. 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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