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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
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<!ENTITY COMMANDNAME "mandos">
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<!ENTITY TIMESTAMP "2009-02-15">
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<!ENTITY TIMESTAMP "2009-12-09">
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<!ENTITY % common SYSTEM "common.ent">
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The server will, by default, continually check that the clients
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are still up. If a client has not been confirmed as being up
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for some time, the client is assumed to be compromised and is no
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longer eligible to receive the encrypted password. The timeout,
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longer eligible to receive the encrypted password. (Manual
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intervention is required to re-enable a client.) The timeout,
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checker program, and interval between checks can be configured
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both globally and per client; see <citerefentry>
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<refentrytitle>mandos-clients.conf</refentrytitle>
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<manvolnum>5</manvolnum></citerefentry>.
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<manvolnum>5</manvolnum></citerefentry>. A client successfully
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receiving its password will also be treated as a successful
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backtrace. This could be considered a feature.
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Currently, if a client is declared <quote>invalid</quote> due to
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having timed out, the server does not record this fact onto
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permanent storage. This has some security implications, see
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<xref linkend="clients"/>.
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Currently, if a client is disabled due to having timed out, the
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server does not record this fact onto permanent storage. This
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has some security implications, see <xref linkend="clients"/>.
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There is currently no way of querying the server of the current
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If a client is compromised, its downtime should be duly noted
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by the server which would therefore declare the client
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invalid. But if the server was ever restarted, it would
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re-read its client list from its configuration file and again
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regard all clients therein as valid, and hence eligible to
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receive their passwords. Therefore, be careful when
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restarting servers if it is suspected that a client has, in
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fact, been compromised by parties who may now be running a
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fake Mandos client with the keys from the non-encrypted
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initial <acronym>RAM</acronym> image of the client host. What
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should be done in that case (if restarting the server program
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really is necessary) is to stop the server program, edit the
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configuration file to omit any suspect clients, and restart
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by the server which would therefore disable the client. But
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if the server was ever restarted, it would re-read its client
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list from its configuration file and again regard all clients
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therein as enabled, and hence eligible to receive their
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passwords. Therefore, be careful when restarting servers if
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it is suspected that a client has, in fact, been compromised
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by parties who may now be running a fake Mandos client with
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the keys from the non-encrypted initial <acronym>RAM</acronym>
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image of the client host. What should be done in that case
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(if restarting the server program really is necessary) is to
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stop the server program, edit the configuration file to omit
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any suspect clients, and restart the server program.
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For more details on client-side security, see