eXtremail Remote Format String ('s)

["mu-b" <mu-b () digit-labs org>]

Bugtraq readers,

eXtremail is a free integrated pop3/smtpd mail daemon for Linux (x86), although
it is free it is closed sourced software. It has been found that the majority of the
newer versions are vulnerable to a remotely exploitable format string condition.
The following versions are confirmed to be vulnerable to this condition:

    eXtremail v1.1.5
    eXtremail v1.1.6
    eXtremail v1.1.7
    eXtremail v1.1.8
    eXtremail v1.1.9

Note: Version 1.1.3 is also presumed to be vulnerable but that version was not
available for testing, although I have strong reason to assume that it is.

The format string problem is located in the flog() function, and is caused by the
use of user defined data as the format string for an fprintf() statement. This problem
can be exploited remotely to yield remote root privileges, through sending
appropriately constructed strings as the arguments to the following commands:

Smtpd - HELO / EHLO / MAIL FROM:<....@....> / RCPT TO:<....@....>
Pop3 - USER (+ others requiring a suitable login).

This issue has been patched as of version 1.1.10, it is advisable that current or
prospective users download this version as soon as possible. This is obtainable
from the eXtremail homepage found at http://www.extremail.com

Exploit code attached....

Yours Sincerly.....
mu-b
___________________________________________________________

mu-b (µb)  (mu-b () digit-labs org)
http://www.digit-labs.org

               "Like German Tourists, the stupid are everywhere"
                               -Arnold 'Judas' Rimmer - Red Dwarf BBC (c)

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