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

[infamous41md@xxxxxxxxxx]

this can't be exploited to execute code, as any non printable characters are
turned into '.' before the buffer is passed to fprintf().  well actually, if
there is some platform where the relevant addresses can be reached with only
printable characters it's possible, but i'm not aware of any such platform.

On Thu, 19 Aug 2004 16:22:55 -0700
"Joshua J. Berry" <condordes@xxxxxxxxxx> wrote:

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


-- 
-sean