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Date:      Thu, 8 Nov 2001 17:32:30 +0100
From:      Martin Karlsson <martin.karlsson@visit.se>
To:        FreeBSD Questions <freebsd-questions@FreeBSD.ORG>
Subject:   Re: Lockdown of FreeBSD machine directly on Net
Message-ID:  <20011108173230.B1542@foo31-249.visit.se>
In-Reply-To: <20011108172755.A1542@foo31-249.visit.se>; from martin.karlsson@visit.se on Thu, Nov 08, 2001 at 05:27:55PM %2B0100
References:  <000201c166a2$d2ed80c0$1401a8c0@tedm.placo.com> <001401c166a9$9b976120$0a00000a@atkielski.com> <20011106180650.A72863@student.uu.se> <00ca01c16794$12a7eba0$0a00000a@atkielski.com> <20011107154930.A7915@student.uu.se> <20011108172755.A1542@foo31-249.visit.se>

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But I suppose that is one of the mayor factors when implementing
security: Some procedures will be very uncomfortable to follow,
but following these procedures will make you happier in the long run.
/Martin

* Martin Karlsson (martin.karlsson@visit.se) wrote:
> Or even watching the sysadmin write in the root password through
> binoculars from across the street. That's bad; I for one hate working in
> a room without windows (glass ones that is ;)).
> 
> /Martin
> * Erik Trulsson (ertr1013@student.uu.se) wrote:
> > On Wed, Nov 07, 2001 at 02:56:58PM +0100, Anthony Atkielski wrote:
> > > Erik writes:
> > > 
> > > > There is no such thing as 100% security.
> > > 
> > > Sure there is.  Shannon proved it.  Some spies and spooks implement it.
> > 
> > No, there is no such thing as 100% security.
> > I assume your comment about Shannon refers to such things as
> > unbreakable cryptos of which the One-Time-Pad is the best known.
> > This is not the same thing as 100% security though.
> > To get 100% security you also need to protect yourself against attacks
> > such as:
> > 
> > a) Somebody breaking into the office and stealing the computers.
> > b) Calling the sysadmin and pretending to be his boss and convince him
> >    to open a hole.
> > c) Reading the password from a Post-It note which some careless
> >    legitimate user left around.
> > d) Sweettalking the secretary into letting them in.
> > e) Bribing the sysadmin.
> > f) Kidnapping the person who knows the password and torturing him/her
> >    until he/she reveals it.
> > g) Blackmail.
> > 
> > 
> > Unless you are fully protected against all these (and many other
> > possible attacks) you do not have 100% security.
> > You might have very good security but not 100%.
> > 
> > 
> > To get a secure system it is not enough to consider things like
> > cryptography and network protocols although those are important.
> > It is also necessary to take into account attacks based on social
> > engineering or physical breakins.
> > 
> > 
> > > 
> > > > This is case where persistence is exactly what
> > > > is needed to crack the system.  One simply tries
> > > > every possible password until one succeeds.
> > > 
> > > With random eight-character alphanumeric passwords and five Telnet login attemps
> > > per second, this will take about 1.25 million years, on average, far longer than
> > > the lifetime of any attacker, persistent or otherwise.  In other words, the
> > > system is completely secure in this context through computational feasibility,
> > > and you can make it theoretically 100% secure as well by installing a lockout
> > > after a certain number of bad password attempts.
> > 
> > The cracker might get lucky and guess the password on the first try.
> > The probability of this happening is extremely low but it is non-zero.
> > Therefore this is not theoretically 100% secure although in practice it
> > is quite secure.
> > 
> > 
> > 
> > Note: When I say 100% security above I really do mean 100%. I do not
> > mean 99.99999% security which might well be obtainable (but probably
> > prohibitively expensive since the cost of implementing such a level of
> > security is likely higher than that which it is supposed to protect.)
> > 
> > 
> > -- 
> > <Insert your favourite quote here.>
> > Erik Trulsson
> > ertr1013@student.uu.se
> > 
> > To Unsubscribe: send mail to majordomo@FreeBSD.org
> > with "unsubscribe freebsd-questions" in the body of the message
> 
> -- 
> ------------------------------------------------
> Martin Karlsson		martin.karlsson@visit.se
> 
> To Unsubscribe: send mail to majordomo@FreeBSD.org
> with "unsubscribe freebsd-questions" in the body of the message

-- 
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