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@@ -1625,6 +1625,130 @@ SRV Records
 
 Security
 ========
+
+Threat Model
+------------
+
+Denial of Service
+~~~~~~~~~~~~~~~~~
+
+The attacker could attempt to prevent delivery of messages to or from the
+victim in order to:
+
+    * Disrupt service or marketing campaign of a commercial competitor.
+    * Censor a discussion or censor a participant in a discussion.
+    * Perform general vandalism.
+
+Threat: Resource Exhaustion
++++++++++++++++++++++++++++
+
+An attacker could cause the victims server to exhaust a particular resource
+(e.g. open TCP connections, CPU, memory, disk storage)
+
+Threat: Unrecoverable Consistency Violations
+++++++++++++++++++++++++++++++++++++++++++++
+
+An attacker could send messages which created an unrecoverable "split-brain"
+state in the cluster such that the victim's servers could no longer dervive a
+consistent view of the chatroom state.
+
+Threat: Bad History
++++++++++++++++++++
+
+An attacker could convince the victim to accept invalid messages which the
+victim would then include in their view of the chatroom history. Other servers
+in the chatroom would reject the invalid messages and potentially reject the
+victims messages as well since they depended on the invalid messages.
+
+Threat: Block Network Traffic
++++++++++++++++++++++++++++++
+
+An attacker could try to firewall traffic between the victim's server and some
+or all of the other servers in the chatroom.
+
+Threat: High Volume of Messages
++++++++++++++++++++++++++++++++
+
+An attacker could send large volumes of messages to a chatroom with the victim
+making the chatroom unusable.
+
+Threat: Banning users without necessary authorisation
++++++++++++++++++++++++++++++++++++++++++++++++++++++
+
+An attacker could attempt to ban a user from a chatroom with the necessary
+authorisation.
+
+Spoofing
+~~~~~~~~
+
+An attacker could try to send a message claiming to be from the victim without
+the victim having sent the message in order to:
+
+* Impersonate the victim while performing illict activity.
+* Obtain privileges of the victim.
+
+Threat: Altering Message Contents
++++++++++++++++++++++++++++++++++
+
+An attacker could try to alter the contents of an existing message from the
+victim.
+
+Threat: Fake Message "origin" Field
++++++++++++++++++++++++++++++++++++
+
+An attacker could try to send a new message purporting to be from the victim
+with a phony "origin" field.
+
+Spamming
+~~~~~~~~
+
+The attacker could try to send a high volume of solicicted or unsolicted
+messages to the victim in order to:
+
+* Find victims for scams.
+* Market unwanted products.
+
+Threat: Unsoliticted Messages
++++++++++++++++++++++++++++++
+
+An attacker could try to send messages to victims who do not wish to receive
+them.
+
+Threat: Abusive Messages
+++++++++++++++++++++++++
+
+An attacker could send abusive or threatening messages to the victim
+
+Spying
+~~~~~~
+
+The attacker could try to access message contents or metadata for messages sent
+by the victim or to the victim that were not intended to reach the attacker in
+order to:
+
+* Gain sensitive personal or commercial information.
+* Impersonate the victim using credentials contained in the messages.
+  (e.g. password reset messages)
+* Discover who the victim was talking to and when.
+
+Threat: Disclosure during Transmission
+++++++++++++++++++++++++++++++++++++++
+
+An attacker could try to expose the message contents or metadata during
+transmission between the servers.
+
+Threat: Disclosure to Servers Outside Chatroom
+++++++++++++++++++++++++++++++++++++++++++++++
+
+An attacker could try to convince servers within a chatroom to send messages to
+a server it controls that was not authorised to be within the chatroom.
+
+Threat: Disclosure to Servers Within Chatroom
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+An attacker could take control of a server within a chatroom to expose message
+contents or metadata for messages in that room.
+
 .. NOTE::
   This section is a work in progress.