Public Vulnerability Reports

Ipswitch IMail IMAP SELECT Command DoS Vulnerability



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.


The vendor has released the following hotfix to fix this vulnerability
in IMail Server 8.15:

The vendor has released the following hotfix to fix this vulnerability
in IMail Server 8.2:
The vendor has released the following hotfix to fix this vulnerability
in Ipswitch Collaboration Suite 2.0:

The associated vendor advisories are available at:


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 (, which standardizes names for
security problems.


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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Copyright © 2005 Verisign, Inc.

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