[ GLSA 200408-19 ] courier-imap: Remote Format String Vulnerability

["Joshua J. Berry" <condordes () gentoo org>]

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Gentoo Linux Security Advisory                           GLSA 200408-19
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                                            http://security.gentoo.org/
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  Severity: High
     Title: courier-imap: Remote Format String Vulnerability
      Date: August 19, 2004
      Bugs: #60865
        ID: 200408-19

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Synopsis
========

There is a format string vulnerability in non-standard configurations
of courier-imapd which may be exploited remotely. An attacker may be
able to execute arbitrary code as the user running courier-imapd
(oftentimes root).

Background
==========

Courier-IMAP is an IMAP server which is part of the Courier mail
system. It provides access only to maildirs.

Affected packages
=================

    -------------------------------------------------------------------
     Package                /   Vulnerable   /              Unaffected
    -------------------------------------------------------------------
  1  net-mail/courier-imap      <= 3.0.2-r1                   >= 3.0.5

Description
===========

There is a format string vulnerability in the auth_debug() function
which can be exploited remotely, potentially leading to arbitrary code
execution as the user running the IMAP daemon (oftentimes root). A
remote attacker may send username or password information containing
printf() format tokens (such as "%s"), which will crash the server or
cause it to execute arbitrary code.

This vulnerability can only be exploited if DEBUG_LOGIN is set to
something other than 0 in the imapd config file.

Impact
======

If DEBUG_LOGIN is enabled in the imapd configuration, a remote attacker
may execute arbitrary code as the root user.

Workaround
==========

Set the DEBUG_LOGIN option in /etc/courier-imap/imapd to 0. (This is
the default value.)

Resolution
==========

All courier-imap users should upgrade to the latest version:

    # emerge sync

    # emerge -pv ">=net-mail/courier-imap-3.0.5"
    # emerge ">=net-mail/courier-imap-3.0.5"

References
==========

  [ 1 ] iDEFENSE Advisory
        http://www.idefense.com/application/poi/display?id=131&type=vulnerabilities&flashstatus=true

Availability
============

This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:

    http://security.gentoo.org/glsa/glsa-200408-19.xml

Concerns?
=========

Security is a primary focus of Gentoo Linux and ensuring the
confidentiality and security of our users machines is of utmost
importance to us. Any security concerns should be addressed to
security () gentoo org or alternatively, you may file a bug at
http://bugs.gentoo.org.

License
=======

Copyright 2004 Gentoo Foundation, Inc; referenced text
belongs to its owner(s).

The contents of this document are licensed under the
Creative Commons - Attribution / Share Alike license.

http://creativecommons.org/licenses/by-sa/1.0

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