Multiple Buffer Overflow Vulnerabilities Found in MERCUR Mail server v.4.2 (SP2) - IMAP protocol

From: Dennis Rand (derat_private)
Date: Fri Jun 06 2003 - 08:26:32 PDT

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    [STATUS, EXAMINE, DELETE, SUBSCRIBE, UNSUBSCRIBE, RENAME, LIST, LSUB, LOGIN,
    CREATE, SELECT]
                          Multiple Buffer Overflow Vulnerabilities
                           Found in MERCUR Mail server v.4.2 (SP2)
                             http://www.atriumsoftwareusa.com/
                             
                                Discovered by Dennis Rand
                                   www.Infowarfare.dk
    ------------------------------------------------------------------------
    
    
    -----[SUMMARY
    Mercur Mail Server is a Windows NT4/2000/XP mail server application, 
    Supporting all the RFC industry standards set for POP3, IMAP4 and SMTP. 
    A versatile application that offers stability, security and scalability 
    designed to meet any size organization from the small business to an 
    enterprise business with thousands of employees or customers. 
    Mercur Mail Server supports an integrated anti-virus engine by Norman, 
    Black List or Open Relay connectivity, ODBC connectivity, remote Windows 
    GUI and Web administration administration access. Mercur Mail Server 
    is the ideal solution for any business.
    
    The problem is multiple Buffer Overflows in the IMAP4 protocol, within the 
    MERCUR IMAP4-Server (v4.02.09), causing the service to shutdown.
    
    
    
    -----[AFFECTED SYSTEMS
    Vulnerable systems:
     * MERCUR Mailserver 4.2 (SP2)- Fileversion : 4.2.14.0
    
    Immune systems:
     * MERCUR Mailserver 4.2 (SP2)- Fileversion : 4.2.15.0 or higher
    
    -----[SEVERITY
    High    -     An attacker is able to cause a DoS attack on the IMAP protocol
                  And the exception handler on the stack is overwritten allowing
    
                  A system compromise with code execution running as SYSTEM.
                  The reason that this is a HIGH is the there is no need to 
                  login on the system to conduct this type of attack.
                  
             
    
    -----[DESCRIPTION OF WHAT THE VULNERABILITY IS
    The Vulnerability is a Buffer Overflow in the MERCUR IMAP4-Server (v4.02.09)
    When a malicious attacker sends a large amount into the EXAMINE, DELETE,
    SUBSCRIBE,
    RENAME, UNSUBSCRIBE, LIST, LSUB, STATUS, LOGIN, CREATE, SELECT the buffer
    will overflow. 
    Sending to many bytes into the buffer will cause the server
    To reject the request and nothing will happen, this is over 8000 chars. 
    
    ---------------------------- [Exploit Code] ----------------------------
         Is made but is being made public later, for auditing use only
            IMAPAuditor at product being developed by www.0x36.org
    ---------------------------- [Exploit Code] ----------------------------
    
    
    When this attack is preformed the IMAP service is terminating, but the rest
    of
    the services keep running. 
    The service has to be started manually, before working properly.
    
    
    -----[DETECTION
    IMAP4rev1 MDaemon 6.7.8 is vulnerable to the above-described attacks. 
    Earlier versions may be susceptible as well. To determine if a specific 
    Implementation is vulnerable, experiment by following the above transcript. 
    
    
    -----[WORK AROUNDS
    Update to version MERCUR Mailserver 4.2 (SP2)- Fileversion : 4.2.15.0 or
    higher
    
    
    -----[VENDOR RESPONSE
    Dear Dennis,
    Our programmers informed us that they have fixed the problem 
    and now they are testing it. I will inform you when a fix is 
    available, it should be soon.
    Thank you for pointing out this problem to us.
    Sincerely,
    Alex Ribeiro
    
    
    -----[DISCLOSURE TIMELINE
    10/05/2003 Found the Vulnerability, and made an analysis.
    13/05/2003 Reported to Vendor. 
    14/05/2003 Recived information from Vendor
    06/06/2003 Public Disclosure.
    
    
    -----[ADDITIONAL INFORMATION
    The vulnerability was discovered and reported by <derat_private> Dennis
    Rand
    
    -----[DISCLAIMER
    The information in this bulletin is provided "AS IS" without warranty of any
    kind. 
    In no event shall we be liable for any damages whatsoever including direct,
    indirect, 
    incidental, consequential, loss of business profits or special damages. 
    



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