SECURITY.NNOV: The Bat! <cr> bug

From: 3APA3A (3APA3Aat_private)
Date: Wed Apr 18 2001 - 06:04:56 PDT

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    There  is more fun then security impact in this issue, but it's a kind
    of DoS and can give a lot of headache to postmasters.
    
    =-------8<----------------------------------
    
    SECURITY.NNOV URL:     http://www.security.nnov.ru
    Topic:                  The Bat! <cr> bug
    Application:            The Bat! 1.51 (latest)
    Vendor:                 RitLabs
    Category:               Denial of Service
    Risk Factor:            Low
    Remote:                 Yes
    Vendor Contacted:       13.04.2001
    Software URL:          http://www.thebat.net
    Vendor URL:            http://www.ritlabs.com
    
    +Introduction:
    
     The  Bat!  Is  very  convenient commercially available MUA for Windows
     with lot of features.
    
    +Details:
    
     While  RETRiving  message  via  POP3  (IMAP  isn't  tested)  The Bat!
     incorrectly  processes  0x0D  (CR)  character if it's not followed by
     0x0A (LF). The Bat! incorrectly calculates end of the message and the
     part  of message is treated as reply from POP3 server. The Bat! fails
     to  receive  the  rest  of  the messages and fails to delete received
     messages  from server. This leads to DoS against user's POP3 account.
     Malformed message can emulate any POP3 server replies.
    
    +Exploitation:
    
     Extract attached "badmessage" and send it, e.g. using
    
       cat badmessage | sendmail -U victimat_private
    
     or copy it to user's mailbox.
     This message causes The Bat! to show something like:
    
       !13.04.2001, 17:51:01: FETCH - Server reports error. The response is: --ERR Wrong User: replace user with your system administrator--
    
     message is crafted to do not contain this text somewhere in the body.
    
    +Workaround:
    
     use  "Dispatch  Mail  on  Server" feature to delete malformed message
     from server or use different MUA.
    
    
    +Solution:
    
     No yet.
    
    +Vendor:
    
     RitLabs  was  contacted  on April, 13 (happy Easter to you, guys). No
     feedback yet.
    
    This  advisory  is being provided to you under RFPolicy v.2 documented
    at http://www.wiretrip.net/rfp/policy.html.
    
    
    --
    http://www.security.nnov.ru
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