1
1
<?xml version="1.0" encoding="UTF-8"?>
2
2
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3
3
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
4
<!ENTITY TIMESTAMP "2012-01-01">
4
<!ENTITY TIMESTAMP "2019-02-09">
5
5
<!ENTITY % common SYSTEM "common.ent">
61
67
The computers run a small client program in the initial RAM disk
62
68
environment which will communicate with a server over a network.
63
69
All network communication is encrypted using TLS. The clients
64
are identified by the server using an OpenPGP key; each client
70
are identified by the server using a TLS public key; each client
65
71
has one unique to it. The server sends the clients an encrypted
66
72
password. The encrypted password is decrypted by the clients
67
using the same OpenPGP key, and the password is then used to
73
using a separate OpenPGP key, and the password is then used to
68
74
unlock the root file system, whereupon the computers can
69
75
continue booting normally.
73
79
<refsect1 id="introduction">
74
80
<title>INTRODUCTION</title>
82
<!-- This paragraph is a combination and paraphrase of two
83
quotes from the 1995 movie “The Usual Suspects”. -->
76
84
You know how it is. You’ve heard of it happening. The Man
77
85
comes and takes away your servers, your friends’ servers, the
78
86
servers of everybody in the same hosting facility. The servers
193
201
No. The server only gives out the passwords to clients which
194
202
have <emphasis>in the TLS handshake</emphasis> proven that
195
they do indeed hold the OpenPGP private key corresponding to
203
they do indeed hold the private key corresponding to that
208
<refsect2 id="sniff">
209
<title>How about sniffing the network traffic and decrypting it
210
later by physically grabbing the Mandos client and using its
213
We only use <acronym>PFS</acronym> (Perfect Forward Security)
214
key exchange algorithms in TLS, which protects against this.
218
<refsect2 id="fakeping">
219
<title>Faking ping replies?</title>
236
<refsect2 id="fakecheck">
237
<title>Faking checker results?</title>
221
The default for the server is to use
239
If the Mandos client does not have an SSH server, the default
240
is for the Mandos server to use
222
241
<quote><literal>fping</literal></quote>, the replies to which
223
242
could be faked to eliminate the timeout. But this could
224
243
easily be changed to any shell command, with any security
225
measures you like. It could, for instance, be changed to an
226
SSH command with strict keychecking, which could not be faked.
227
Or IPsec could be used for the ping packets, making them
244
measures you like. If the Mandos client
245
<emphasis>has</emphasis> an SSH server, the default
246
configuration (as generated by
247
<command>mandos-keygen</command> with the
248
<option>--password</option> option) is for the Mandos server
249
to use an <command>ssh-keyscan</command> command with strict
250
keychecking, which can not be faked. Alternatively, IPsec
251
could be used for the ping packets, making them secure.
added
removed
intro.xml
