Re: UNIX shell modem access vulnerabilities

[smb () RESEARCH ATT COM (Steve Bellovin)]

Problems with tty access not being revoked are not new -- they've occurred
for at least 20 years.  Circa 1988, I devised a strong solution; however,
I was unable to get it into System V in that form.  Today, with the advent
of several different free UNIX-like systems, it may be worth revisiting
the question.  See http://www.research.att.com/~smb/papers/sessext.ps
(or .pdf) for a description of my work.  (Btw -- while I can't guarantee
that there are no patent claims lurking around, I did not file anything,
and I don't know of anyone else who might claim something.)