Ipswitch Collaboration Suite SMTP Format String Vulnerability

iDEFENSE Security Advisory 12.06.05
www.idefense.com/application/poi/display?id=346&type=vulnerabilities
December 6, 2005

I. BACKGROUND

Ipswitch Collaboration Suite provides e-mail and real-time
collaboration, calendar and contact list sharing, and protection from
spam and viruses, all delivered in an easy to use suite.

     http://www.ipswitch.com/products/collaboration/index.asp

II. DESCRIPTION

Remote exploitation of a format string vulnerability in Ipswitch
IMail allows remote attackers to execute arbitrary code.

The vulnerability specifically exists due to improper use of functions
which allow format specifiers in the SMTP service included with ICS.
Remote attackers can supply format string values to certain string
functions to cause memory corruption leading to remote code execution.
The vulnerability may be exploited by supplying specially crafted
strings to any of the following SMTP commands: EXPN, MAIL, MAIL FROM,
RCPT TO. All of the commands are handled by the same function which
parses user-supplied input strings. The following debugger session
shows a backtrace with user-supplied strings as values. With properly
constructed input value, the strings would be interpreted as memory
addresses that would be executed upon returning from the current
function.

[..]
00A7F370   006020A0
00A7F374   00A7F634  ASCII 5B,"192.168.242.1] MAIL
  FROM:C:\apps\Ipswitch\Collaboration
  Suite\IMail\spool\T94e8013e00000005"
00A7F378   00000000
00A7F37C   00000000
00A7F380   7C34FC0B  RETURN to MSVCR71.7C34FC0B from MSVCR71.write_char
00A7F384   00602048
00A7F388   00A7F648  ASCII 20,"FROM:C:\apps\Ipswitch\Collaborat"
[..]

III. ANALYSIS

Successful exploitation of the format string vulnerability allows
unauthenticated remote attackers to execute arbitrary code. Ipswitch
mail services are commonly configured to allow untrusted access. The
use of a firewall or other mitigating strategy is highly recommended
due to the nature of this vulnerability. The IMail SMTP server is
installed by default.

IV. DETECTION

iDEFENSE Labs has confirmed the existence of this vulnerability in
Ipswitch Collaboration Suite 8.20.

V. WORKAROUND

iDEFENSE is currently unaware of any effective workarounds for this
issue. Access to the affected host should be filtered at the network
boundary if global accessibility is not required. Restricting access to
only trusted hosts and networks may reduce the likelihood of
exploitation.

VI. VENDOR RESPONSE

Ipswitch Collaboration Suite 2.02 has been released to address this
issue and is available for download at:

  http://www.ipswitch.com/support/ics/updates/ics202.asp

IMail Server 8.22  has been released to address this issue and is
available for download at:

  
http://www.ipswitch.com/support/imail/releases/imail_professional/im822.asp

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CAN-2005-2931 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

09/08/2005  Initial vendor notification
09/13/2005  Initial vendor response
10/06/2005  Coordinated public disclosure

IX. CREDIT

iDEFENSE credits Nico with the discovery of this vulnerability.

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X. LEGAL NOTICES

Copyright © 2005 iDEFENSE, Inc.

Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without the express
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part of this alert in any other medium other than electronically, please
email customerservice@idefense.com 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.