Subject: iDEFENSE Security Advisory 05.24.05: Ipswitch IMail IMAP LSUB DoS Vulnerability
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Date: Tue, 24 May 2005 16:09:16 -0400
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Thread-Topic: iDEFENSE Security Advisory 05.24.05: Ipswitch IMail IMAP LSUB DoS Vulnerability
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From: "iDEFENSE Labs" <labs-no-reply@idefense.com.>
To: <bugtraq@securityfocus.com.>, <vulnwatch@vulnwatch.org.>,
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Ipswitch IMail IMAP LSUB DoS Vulnerability
iDEFENSE Security Advisory 05.24.05
www.idefense.com/application/poi/display?id=3D245&type=3Dvulnerabilities
May 24, 2005
I. BACKGROUND
Ipswitch Collaboration Suite (ICS) is a comprehensive communication and=20
collaboration solution for Microsoft Windows with a customer base of=20
over 53 million users. More information is available on the vendor's=20
website:
http://www.ipswitch.com/products/IMail_Server/index.html
II. DESCRIPTION
Remote exploitation of a denial of service (DoS) vulnerability in=20
Ipswitch Inc.'s IMail IMAP daemon allows attackers to cause 100 percent=20
CPU use on the server, thereby preventing legitimate users from=20
retrieving e-mail.
The problem specifically exists within IMAPD32.EXE upon parsing a=20
malformed LSUB command. An attacker can cause the daemon to produce=20
heavy load by transmitting a long string of NULL characters to the=20
'LSUB' IMAP directive. This, in turn, causes an infinite loop,=20
eventually exhausting all available system resources and causing a=20
denial of service.
III. ANALYSIS
Exploitation allows unauthenticated remote attackers to render the IMAP=20
server useless, thereby preventing legitimate users from retrieving e-
mail. This attack takes few resources to launch and can be repeated=20
to ensure that an unpatched system is unable to recover. Exploitation=20
requires a valid IMAP account, thus limiting the impact of this=20
vulnerability.
IV. DETECTION
iDEFENSE has confirmed the existence of this vulnerability in Ipswitch=20
IMail version 8.13. It is suspected that earlier versions are also=20
vulnerable.
V. WORKAROUND
As this vulnerability is exploited after authentication occurs, ensuring
that only trusted users have accounts can mitigate the risk somwhat. As=20
a more effective workaround, consider limiting access to the IMAP server
by filtering TCP port 143. If possible, consider disabling IMAP and=20
forcing users to use POP3.
VI. VENDOR RESPONSE
The vendor has released the following patch to fix this vulnerability:
ftp://ftp.ipswitch.com/Ipswitch/Product_Support/IMail/imail82hf2.exe
The associated vendor advisory can be found at:
http://www.ipswitch.com/support/imail/releases/imail_professional/im82hf
2.html
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CAN-2005-1249 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
04/25/2005 Initial vendor notification
05/10/2005 Initial vendor response
05/24/2005 Public disclosure
IX. CREDIT
The discoverer of the first vulnerability wishes to remain anonymous.
Get paid for vulnerability research
http://www.idefense.com/poi/teams/vcp.jsp
Free tools, research and upcoming events
http://labs.idefense.com
X. LEGAL NOTICES
Copyright (c) 2005 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
email [email protected] 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.
