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the root file, and continue booting.
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Now, of course the initial RAM disk image is not on the encrypted
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root file system, so anyone who would come and take the the whole
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computer would have the Mandos client key when they took the server
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offline and read the disk with their own tools. *But*, by then the
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Mandos server will have detected that the original server is no
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longer online and will no longer give out the encrypted key. The
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timing here is the only real weak point, and the method, frequency
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and timeout of checking can be adjusted to any desired level of
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root file system, so anyone who had physical access could take the
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server offline and read the disk with their own tools to get the
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authentication keys used by a client. *But*, by then the Mandos
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server should notice that the original server has been offline for
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too long, and will no longer give out the encrypted key. The timing
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here is the only real weak point, and the method, frequency and
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timeout of the server’s checking can be adjusted to any desired
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(The encrypted keys on the Mandos server is on its normal file
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system, so those are safe, provided the root file system of that
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system, so those are safe, provided the root file system of *that*
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server is encrypted.)
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* FAQ - couldn’t the security be defeated by...
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all *before* the Mandos server timeout kicks in and the Mandos
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server refuses to give out the key to anyone.
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As the typical SOP seems to be to barge in and turn off and grab
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*all* computers to maybe look at them months later, this is not
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Now, as the typical SOP seems to be to barge in and turn off and
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grab *all* computers, to maybe look at them months later, this is
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not likely. If someone does that, the whole system *will* lock
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itself up completely, since Mandos servers are no longer running.
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For sophisticated attackers who *could* do the clever thing, *and*
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had physical access to the server for enough time, it would be
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simpler to get a key for an encrypted file system by using hardware
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memory scanners and reading it right off the memory bus.
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Nope, the network stuff is all done over TLS, which provides
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** Physically grabbing the Mandos server computer?
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You could protect *that* computer the old-fashioned way, with a
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must-type-in-the-password-at-boot method. Or you could have two
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computers be the Mandos server for each other. (Multiple Mandos
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servers can coexist on a network without any trouble. They do not
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clash, and clients will try all available servers.)
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computers be the Mandos server for each other.
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Multiple Mandos servers can coexist on a network without any
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trouble. They do not clash, and clients will try all available
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servers. This means that if just one reboots then the other can
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bring it back up, but if both reboots at the same time they will
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stay down until someone types in the password on one of them.
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** Faking ping replies?
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The default for the server is to use "fping", the replies to which
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* Security Summary
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So, in summary: The only weakness in the Mandos system is from
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1. The power to come in and physically take your servers, and
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1. The power to come in and physically take your servers, *and*
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117
2. The cunning and patience to do it carefully, one at a time, and
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*quickly*, faking Mandos client/server responses for each one
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before the timeout.
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these attributes, they do not, probably, constitute the majority.
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If you *do* face such opponents, you must figure that they could
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just as well open your servers and read the keys right off the
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memory by running wires to the memory bus.
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just as well open your servers and read the file system keys right
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off the memory by running wires to the memory bus.
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What this system is designed to protect against is *not* such
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determined, focused, and competent attacks, but against the early
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morning knock on your door and the sudden absence of all servers in
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What Mandos is designed to protect against is *not* such determined,
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focused, and competent attacks, but against the early morning knock
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on your door and the sudden absence of all the servers in your
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server room. Which it does nicely.
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README
