Possible Security Flaw in Trend Micro's InterScan FTP Proxy

From: Lherisson, Karl C. (Karlat_private)
Date: Mon Jun 14 1999 - 14:47:17 PDT

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    Hi my name is Karl C. Lherisson a network consultant at a securities
    firm.
    I am writing to inform you that I recently purchased Trend Micro's
    InterScan product for its ability to scan email for viruses and to
    prevent SPAM from being relayed of our SMTP server.  I also decided to
    look into the FTP proxy feature that is included but I found a possible
    security hole in the product.  When using InterScan version 3.0 as a
    stand alone proxy there is no way to limit who can have access to the
    FTP proxy.  Unlike the SMTP portion, where one can specify valid source
    IP addresses that are able to relay mail, anyone on the Internet who
    knows the IP address of the InterScan FTP proxy can use it to log onto
    another network and basically hide their identity.
    
    So if I were a "hacker" and I wanted to launch an FTP attack on lets say
    
    COMPANY A, and I know there is a Trend Micro InterScan FTP Proxy server
    at
    COMPANY B, well I would login to COMPANY B proxy server and then connect
    to
    COMPANY A.  What makes matters worse is that InterScan 3.0 does not keep
    a
    log of FTP connections (basically making the hacker anonymous), and the
    software will perform the job of checking the hacker's files for
    viruses.
    Additionally, if COMPANY A found out that they were infiltrated in some
    way,
    it would appear that it originated from COMPANY B.
    
    Fortunately, the FTP Proxy Server can be disabled but this kills 1/3
    of the product functionality.
    
    -
    Karl C. Lherisson
    karlat_private
    Network Consultant
    



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