Activity termination protocols fail or are interrupted so that
termination does not complete properly and the protocol is taken over by the
attacker. Examples include modem hangup failures leaving logged-in terminal
sessions open to abuse, interrupted telnet sessions taken over by attackers,
preventing proper protocol completion as in the Internet SYN attacks so as
to deny subsequent services, and refusing to completely disconnect from a
call-back modem at the CO, causing the call-back mechanism to become
ineffective.
Complexity: These classes of attacks are normally simple to
carry out with probabilistic effects depending on the environment.
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