Hypermail SSI Vulnerability

From: qDefense Penetration Testing (advisoriesat_private)
Date: Mon Nov 19 2001 - 11:36:55 PST

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    Hypermail SSI Vulnerability
    qDefense Advisory Number QDAV-2001-11-1
    
    Product: Hypermail
    
    Vendor: Hypermail Development (http://www.hypermail.org)
    
    Severity: Remote; Attacker may be able to execute arbitrary commands on 
    servers that run Hypermail and SSI
    
    Vendor Status: Vendor contacted; patch released
    
    In Short: Hypermail can be used to create arbitrary files, with arbitrary 
    extensions, on the server, which may then possibly be used to execute SSI 
    commands.
    
    
    The current version of this document is available at 
    http://qDefense.com/Advisories/QDAV-2001-11-1.html.
    
    Details:
    
    Hypermail converts e-mails into HTML. It is generally used to automatically 
    create web archives of mailing lists. When e-mails are archived, 
    attachments which are included are archived as well. The attachments are 
    not modified before archival, and they are stored under the filename 
    contained in the e-mail.
    
    An attacker can therefore create an arbitrary file on the web server with 
    an arbitrary extension. If the server supports SSI, an attacker can include 
    SSI commands in a file, give it the SSI extension (normally .shtml), and 
    mail it. This will create the desired file on the server. The attacker can 
    than cause the server to execute those SSI commands by requesting the 
    attachment.
    
    It should be noted that creation of arbitrary files on a web server carries 
    with it additional insecurites besides SSI, and therefore even servers that 
    do not support SSI may be vulnerable.
    
    Solution:
    
    Hypermail has been patched to convert .shtml extensions to .html. As of 
    this writing, no further correction has been taken.
    
    Servers should never allow SSI, CGI, or any other type of server processed 
    content in the hypermail directory.
    
    (C) 2001 qDefense Penetration Testing. qDefense Penetration Testing is a 
    subsidiary of Computer Modeling Corp.
    This document may be reproduced, in whole or in part, provided that no 
    modifications are made and that proper credit is given. Additionally, if it 
    is made available through hypertext, it must be accompanied by a link to 
    the qDefense Penetration Testing web site, http://qdefense.com.
    



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