Move securitY threat model docs into specification

docs/server-server/security-threat-model.rst

-Overview
-========
-
-Scope
------
-
-This document considers threats specific to the server to server federation 
-synapse protocol.
-
-
-Attacker
---------
-
-It is assumed that the attacker can see and manipulate all network traffic 
-between any of the servers and may be in control of one or more homeservers 
-participating in the federation protocol.
-
-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.
-
-

docs/specification.rst

@@ -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.