Re: NT/Exceed D.O.S.

[david.poythress () BENDER TZO COM (David Poythress)]

This seems to have been fixed at some point, connecting and/or spewing
random data to exceedhost 6000-6010 has no discenrible effect on exceed
6.1.0 under win98 or NTsp4.

A denial of service is still possible though: Exceed defaults to allowing
128 connections from the xdm host, but counts a telnet connection as though
it were a connection from a valid X client.  Once the max number of
connections is reached, subsequent attempts to the X port range are refused.

--
     David Poythress                               dp () qni com

          "Grammar, which controls even kings ..." --Moliere


                -----Original Message-----
                From:   LaFournaise, Chris J.
[mailto:cjlafournaise () ESCOCORP COM]
                Sent:   Tuesday, April 27, 1999 15:29
                To:     BUGTRAQ () netspace org
                Subject:        NT/Exceed D.O.S.

                This is regarding Hummingbird's Exceed X emulator v5 (and
possibly v6)
                running on Windows NT.  I haven't tested Win95/98.

                The Exceed X server allows inbound TCP connections on port
6000 from the XDM
                host.  If someone uses telnet from the XDM host to connect
to a PC running
                Exceed on port 6000 and enters any garbage text, the X
server will hang and
                the Exceed session is frozen for good.

                I have notified Hummingbird via their tech support web site
but have not
                received a response yet.

                Chris LaFournaise
                cjlafournaise () escocorp com