🚀 go-pugleaf

In article <21378@rpp386.lonestar.org>, John F. Haugh II writes:
>In article <1992Aug14.190446.11355@hpcvusn.cv.hp.com> Mark Rowe writes:
>> ... {example of covert channel using the system mail system ending with
>> the statement that what makes the channel covert} ...
>> is that the message is hidden or disguised or masquerading as
>> something else as opposed to an overt channel where the information is
>> obvious and undisguised (or disguised in some understood manner such
>> as encrypting).
> 
> ...
> {discussion pointing out how MAC would prevent the use of my example}
> ...
> 
> What you are describing sounds more like busted MAC than a covert
> channel.

It is true that properly implemented MAC would prevent the use of my
example.  That does not in any way prevent this from being an example
of a covert channel, it's simply a covert channel that can be eliminated
by MAC.  MAC does not define a covert channel.  What defines a covert
channel is how the data is being transmitted.  It is either overt or
covert.  An overt channel is a channel that transmits data in a known
manner as intended by the system administrators.  A covert channel is
anything else.

Mark Rowe             email: mark@hpcvlx.cv.hp.com
Hewlett Packard       voice: (503) 750-3246
Corvallis, OR         FAX:   (503) 750-3788