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Gentoo Linux Security Advisory                           GLSA 200408-19
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                                            https://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
        ;type=vulnerabilities&flashstatus=true

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

    https://security.gentoo.org/glsa/200408-19

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
https://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.

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