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RE: [Netconf] Sec-Dir Review: draft-mm-netconf-time-capability-05.tx

2015-07-30 01:43:36
Hi Andy,

You make a good point.
We intend to add text (see below) that describes this point in the next version 
of the draft.
Please let us know if you have further comments.


Here is the updated text on the last paragraph of the security section:

This YANG module defines the <cancel-schedule> RPC. This RPC may be considered 
sensitive or vulnerable in some network environments. Since the value of the 
<schedule-id> is known to all the clients that are subscribed to notifications 
from the server, the <cancel-schedule> RPC may be used maliciously to attack 
servers by canceling their pending RPCs. This attack is addressed in two 
layers: (i) security at the transport layer, limiting the attack only to 
clients that have successfully initiated a secure session with the server, and 
(ii) the authorization level required to cancel an RPC should be the same as 
the level required to schedule it, limiting the attack only to attackers with 
an authorization level that is equal to or higher than that of the client that 
initiated the scheduled RPC.


Thanks,
Tal.


From: Netconf [mailto:netconf-bounces(_at_)ietf(_dot_)org] On Behalf Of Andy 
Bierman
Sent: Thursday, July 30, 2015 12:40 AM
To: Olafur Gudmundsson
Cc: secdir(_at_)ietf(_dot_)org; 
draft-mm-netconf-time-capability(_dot_)all(_at_)ietf(_dot_)org; ietf; Netconf
Subject: Re: [Netconf] Sec-Dir Review: draft-mm-netconf-time-capability-05.tx

Hi,

I am curious if this is a security concern.
When an event is scheduled, the ID and its scheduled time
are sent out in a notification to potentially all clients.


notification netconf-scheduled-message {

        leaf schedule-id {

          type string;

          description

            "The ID of the scheduled message.";

        }



        leaf scheduled-time {

          type yang:date-and-time;

          description

            "The time at which the RPC is scheduled to be performed.";

        }



        description

          "Indicates that a scheduled message was received.";

        reference

          
"draft-mm-netconf-time-capability<https://tools.ietf.org/html/draft-mm-netconf-time-capability>:

           Time Capability in NETCONF";

      }



Any client can get these notifications and know the ID (to cancel it)
and the scheduled time.

Is is a security issue that any client can get the schedule-id
and use it to cancel the scheduled RPC?


Andy


On Wed, Jul 29, 2015 at 2:15 PM, Olafur Gudmundsson 
<ogud(_at_)ogud(_dot_)com<mailto:ogud(_at_)ogud(_dot_)com>> wrote:
I have reviewed this document as part of the security directorate's
ongoing effort to review all IETF documents being processed by the
IESG.  These comments were written primarily for the benefit of the
security area directors.  Document editors and WG chairs should treat
these comments just like any other last call comments.

This document is ready for publication
The document is well written.

The security considerations are clear and accurate. I would like highlight one 
omission though.
This capability allows an attacker once it has gained access to schedule events 
in the future even
though attackers access has been detected and revoked.

Olafur

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