Bugtraq mailing list archives

Re: Vulnerabilities in Checkpoint FW-1 version 3.x and maybe 4.x


From: Richard.Scott () BESTBUY COM (Scott, Richard)
Date: Fri, 21 Jan 2000 15:43:48 -0600


        Root>
        There are two vulnerabilities in FW-1.  The first is an
authentication
        issue, the other  is a configuration issue.  Since I don't have a
copy
        of 4.x FW-1 handy maybe someone can check it for me.

        #1
        The basic authentication used in Checkpoint FW-1 used for
        inside/outbound and outside/inbound allows unlimited attempts to
        authenticate without a timeout or disconnect between unsuccessful
        attempts.  To make matters worse, the attempt at authentication will
let
        you know if you have the wrong username before you are allowed to
enter
        in the passsword.

        The exploit is trivial, grind away at user names until you hit one
that
        works and then grind away at passwords with the username you just
found
        until you find one that works.

        For an example of this, set authentication on the FW-1 software to
        authenticate telnet connections.  Telent to a destination past the
        firewall, when prompted for a username, pound away.  A script could
        crack the authentication in a very short time.

        The workaround is to use Checkpoint's encrypted authentication
program
        "SecuRemote" and not allow clear text authentication (browser based,
        telnet, etc.) to destinations beyond the firewall.

        Surely this work around doesn't work.  Unless I am mistaken, it
matters not whether you use the encrypted method or not.  The problem is the
authentication can be brute force until the cows come home.  Using
encryption isn't the key, logging failed attempts and account closure would
be better, along with not hinting at usernames too!
        Whether the authentication method does this anti brute force check I
as yet do not know.

        Cheers
        r.

Richard Scott   
BestBuy.Com
* Best Buy World Headquarters
7075 Flying Cloud Drive
Eden Prairie, MN 55344 USA

The views expressed in this email do not represent Best Buy
        or any of its subsidiaries.


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