[bit.listserv.ibmtcp-l] Telnet Session Takeover?

PMW1@psuvm.psu.edu (Peter M. Weiss) (08/15/90)

We are very concerned about unauthorized and/or illegal use of resources
on our TCP hosts by taking advantage of weaknesses in the TCP
specifications and/or implementations.

For TCP session initiation and for already established TCP connections
to TCP hosts, what will the products do when receiving packets with
acknowledgement sequence numbers greater than expected, including
maximal acknowledgement sequence numbers?

This might occur when an unauthorized client host attempts to spoof an
TCP server host (assume that the client knows the higher level
transaction protocol such as TN3270 and specific transaction dialogues).
How is it possible, for a rogue host, by misrepresenting its IP address
and/or guessing the acknowledgement numbers, to either initiate a TCP
session with various TCP products or invade an ongoing legitimate
session?

Peter M. Weiss,
SE For TP
Penn State University - Management Services
31 Shields Bldg
University Park, PA 16802
814 863 1843