Subject: WG ACTION: 1 week to discuss [LL48] Some security text should be relocated

From: Erik Guttman <[email-masked]>
Date: Thu, 18 Mar 2004 12:08:25 +0100 (MET)

Please respond to the following issue in the next week, ending 25 Mar
04.  If no response is obtained by then, the assumption will be to
accept the proposed resolution.

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LL48

Description of Issue: Some security section text should be relocated
Submitter Name:       Margaret Wasserman
Submitter Email:      
Date submitted:       20 Feb 04
Reference:            
(T=tech, E=edit):     E
Priority (S must, 1 Should, 2 May fix): 1
Section:               5, 2.5
Rationale/Explanation: 
Long Description:

        The "Security Considerations" section contains the following
        band-aid that should have been included in the earlier text
        that describes how to handle address collision:

  "Implementations and users should also note that a node that gives up
  an address and reconfigures, as required by section 2.5, allows the
  possibility that another node can easily successfully hijack existing
  TCP connections. Before abandoning an address due to a conflict,
  hosts SHOULD actively attempt to reset any existing connections using
  that address."

Proposed Change:

Section 5 text changes from:

   Implementations and users should also note that a node that gives up
   an address and reconfigures, as required by section 2.5, allows the
   possibility that another node can easily successfully hijack existing
   TCP connections. Before abandoning an address due to a conflict,
   hosts SHOULD actively attempt to reset any existing connections using
   that address.

to:
   Implementations and users should also note that a node that gives up
   an address and reconfigures, as required by section 2.5, allows the
   possibility that another node can easily successfully hijack existing
   TCP connections. 

Section 2.5 text changes from:

It is not possible for two
   different hosts using the same IP address on the same network to
   operate reliably.

   Immediately configuring a new address as soon as the conflict is
   detected is the best way to restore useful communication as quickly
   as possible. 
to:

   It is not possible for two
   different hosts using the same IP address on the same network to
   operate reliably.
+
+  Before abandoning an address due to a conflict, hosts SHOULD 
+  actively attempt to reset any existing connections using that 
+  address.  This mitigates some security threats posed by address
+  reconfiguration, as discussed in Section 5.
+
   Immediately configuring a new address as soon as the conflict is
   detected is the best way to restore useful communication as quickly
   as possible. 

----
Erik