RE: FTP Window of opportunity?

From: Jerry Shenk (jshenk_at_decommunications.com)
Date: 03/24/04

  • Next message: Anders Thulin: "Re: FTP Window of opportunity?"
    To: <pen-test@securityfocus.com>
    Date: Tue, 23 Mar 2004 22:36:53 -0500
    
    

    I'd use a sniffer to log monitor what actual packets are being received
    from the "ftp server" to see what scanner is right. It would seem to me
    that ISS should be getting something back if it's claiming that the port
    is open. You could run a sniffing in the path of the traffic between
    the scanning machine and the ftp server and set it to only log the
    traffic between that pair.

    It seems quite normal to get results back from an automated tool that
    conflict with something else. Then the pen tester needs to dig a little
    deeper and analyze what actually happened.

    BTW, some firewalls (Raptor at least) intentionally respond to all kinds
    of crazy traffic. It seems that they intentionally try to confuse an
    attacker (or pen tester;) by allowing connections to ports that aren't
    really open.

    -----Original Message-----
    From: C Ryll [mailto:carolynryll@hotmail.com]
    Sent: Tuesday, March 23, 2004 4:50 PM
    To: pen-test@securityfocus.com
    Subject: FTP Window of opportunity?

    I recently assessed a system in which I already know its configuration
    (and
    have full legal rights to). FTP is purposefully not running, as well as
    blocked by the firewall.
    When I scan with ISS, the FTP port shows up. When I use NMap, it does
    not
    show FTP's port.
    Because of the discrepancy, I tried to manually FTP into the system. It
    actually said "Connected...", hung for about 10 seconds, and then said
    "Connection Terminated."
    (As a baseline, telnet's port is also blocked by the firewall, and does
    not
    show up in scans - essentially, results for telnet are as expected).

    With ISS, I'm assuming that it saw "Connected..." and showed me that
    port.
    My guess would be that NMap waited around to try something else, but saw

    "Connection Terminated" and didn't list it.

    However, as I said previously, seeing that it actually says "Connected",
    and
    then hangs for about 10 seconds before terminating:
    1). Can I use this behavior to my advantage somehow? If yes, how?
    2). Is there a known explanation to this?

    The firewall is the Internet Connection firewall, and I am curious if it

    requires the ftp port inadvertently for its functioning when checking
    the
    incoming packets...

    While I can make some changes to the system (like shutting off certain
    services and shutting off the firewall), I cannot modify it such that I
    can
    try another firewall or anything else like that.

    Any help is greatly appreciated.
    Carolyn.

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  • Next message: Anders Thulin: "Re: FTP Window of opportunity?"

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