wiretapping techniques

[John Roberts]

With few exceptions, I think the following can be considered true:
  1) A network can not be considered secure if the physical links are 
     not secure.
  2) Unless you have taken extraordinary measures, your equipment is
     probably susceptible to electronic eavesdropping. These measures are
     generally expensive, and unlikely to be implemented except at
     sensitive sites. Some of these measures are described in the appropriate
     government documents (which may be classified).

I think that open discussion of weak points and breakin techniques is likely
to cause much more harm than good, since not everyone will be willing and
able to take measures, and presumably a number of people who are willing but
unable to break into other systems will take advantage of the information. I
do not object to general cautions, but discussion of specific techniques to
break security seem to be way out of line. (Or perhaps I'm wrong, and we
should start posting circuit diagrams of spy equipment :-)

As an example of a more reasonable approach, if you should happen to 
discover a way to break into any Unix system, DO NOT post it to the net
as a public service. You might quietly send a note to the designers, and
they might come up with a patch and quietly distribute it, perhaps without
even saying what it's for, and everyone can laugh about the situation
afterward. For situations where the problem is unlikely to be fixed
(wiretapping, etc.), EXTREME caution should be used in informing the users 
that there is a security problem.

<Standard disclaimers.>                        John Roberts
                                               roberts at cmr.icst.nbs.gov