Public Vulnerability Reports

Ipswitch IMail IMAP LOGIN Remote Buffer Overflow Vulnerabilities

05.24.05

BACKGROUND

Ipswitch Collaboration Suite (ICS) is a comprehensive communication and
collaboration solution for Microsoft Windows with a customer base of
over 53 million users. More information is available on the vendor's
website:

     http://www.ipswitch.com/products/IMail_Server/index.html

DESCRIPTION

Remote exploitation of several buffer overflow vulnerabilities in
Ipswitch Inc.'s Imail IMAP server allows attackers to execute arbitrary
code with System privileges.

The first vulnerability specifically exists in the handling of a long
username to the LOGIN command. A long username argument of approximately
2,000 bytes will cause a stack based unicode string buffer overflow
providing the attacker with partial control over EIP. As this
vulnerability is in the LOGIN command itself, valid credentials are not
required.

The second vulnerability also exists in the handling of the LOGIN
command username argument, however it lends itself to easier
exploitation. If a large username starting with one of several special
characters is specified, a stack overflow occurs, allowing an attacker
to overwrite the saved instruction pointer and control execution flow.
Included in the list of special characters are the following: % : * @ &

Both of these vulnerabilities can lead to the execution of arbitrary
code.

ANALYSIS

Successful exploitation allows remote attackers to execute arbitrary
code with System privileges. Valid credentials are not required to for
exploitation, which heightens the impact of this vulnerability.

DETECTION

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 also
vulnerable.

WORKAROUND

As this vulnerability is exploited before authentication occurs, the
only effective workaround is to limit access to the IMAP server by
filtering TCP port 143. If possible, consider disabling IMAP and forcing
users to use POP3.

VENDOR RESPONSE

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

   ftp://ftp.ipswitch.com/Ipswitch/Product_Support/IMail/imail82hf2.exe

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

   ftp://ftp.ipswitch.com/Ipswitch/Product_Support/IMail/imail82hf2.exe
  
The vendor has released the following hotfix to fix this vulnerability
in Ipswitch Collaboration Suite 2.0:

   http://ftp.ipswitch.com/ipswitch/Product_Support/ICS/ICS2hf2.exe

The associated vendor advisories are available at:

http://www.ipswitch.com/Support/imail/releases/imail_professional/im815hf2.html
http://www.ipswitch.com/support/imail/releases/imail_professional/im82hf2.html
http://www.ipswitch.com/Support/ICS/updates/ics2hf2.html

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CAN-2005-1255 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org), which standardizes names for
security problems.

DISCLOSURE TIMELINE

04/25/2005   Initial vendor notification
05/10/2005   Initial vendor response
05/24/2005   Public disclosure

CREDIT

The discoverer of the first vulnerability wishes to remain anonymous.
iDEFENSE Labs is credited with the discovery of the second vulnerability.

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LEGAL NOTICES

Copyright © 2005 Verisign, 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
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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.