[原文]Stack-based buffer overflow in the IMAP server for Ipswitch IMail 8.12 and 8.13, and other versions before IMail Server 8.2 Hotfix 2, allows remote authenticated users to cause a denial of service (crash) via a SELECT command with a large argument.
iDEFENSE Security Advisory 05.24.05-5 - Remote exploitation of a denial of service vulnerability in Ipswitch Inc.'s Imail IMAP server allows attackers to crash the target service thereby preventing legitimate usage. Version 8.13 and 8.12 are confirmed vulnerable. Earlier versions may be susceptible as well.
Ipswitch IMail IMAP SELECT Command DoS Vulnerability
iDEFENSE Security Advisory 05.24.05
May 24, 2005
Ipswitch IMail server is a Windows based messaging solution with a
customer base of over 53 million users. More information about the
application is available at:
Remote exploitation of a denial of service vulnerability in Ipswitch
Inc.'s Imail IMAP server allows attackers to crash the target service
thereby preventing legitimate usage.
The problem specifically exists in the handling of long arguments to the
SELECT command. When a string approximately 260 bytes in size is
supplied a stack-based buffer overflow occurs that results in an
unhandled access violation forcing the daemon to exit. The issue is not
believed to be further exploitable.
Successful exploitation allows remote to crash vulnerable IMAP servers
and thereby prevent legitimate usage. The SELECT command is only
available post authentication and therefore valid credentials are
required to exploit this vulnerability
iDEFENSE has confirmed the existence of this vulnerability in the latest
version of Ipswitch IMAIL, version 8.13. Version 8.12 is also confirmed
as vulnerable. It is suspected that earlier versions are vulnerable as
As this vulnerability is exploited after authentication occurs, ensuring
that only trusted users have accounts can mitigate the risk somwhat. As
a more effective workaround, consider limiting access to the IMAP server
by filtering TCP port 143. If possible, consider disabling IMAP and
forcing users to use POP3.
VI. VENDOR RESPONSE
The vendor has released the following patch to fix this vulnerability:
The associated vendor advisory can be found at:
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CAN-2005-1254 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org), which standardizes names for
VIII. DISCLOSURE TIMELINE
04/15/2005 Initial vendor notification
05/10/2005 Initial vendor response
05/24/2005 Coordinated public disclosure
Sebastian Apelt is credited with this discovery.
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X. LEGAL NOTICES
Copyright (c) 2005 iDEFENSE, Inc.
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at the time of publishing based on currently available information. Use
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A remote overflow exists in IMail Server. The IMAP service (IMAP4D32.EXE) fails to perform proper bounds checking resulting in a buffer overflow. By passing an overly long string to the 'SELECT' command, a remote attacker can cause the IMAP service to crash resulting in a loss of availability.
Upgrade to version 8.2 Hotfix 2 or higher, as it has been reported to fix this vulnerability. An upgrade is required as there are no known workarounds.