Qin and Christian: 

Thank you for your prompt attention to the privacy issue.  
I'm sure Christian will respond in a bit - since he might be in PDT time-zone. 

Once you have a solution you both like, we should
validate the privacy changes to the security considerations section with the 
Yang-doctors, OPS-ADs, and Security-ADs.  

Martin's watching this thread so I'm sure he'll help us out as well. 

Sue 

-----Original Message-----
From: i2rs [mailto:i2rs-boun...@ietf.org] On Behalf Of Qin Wu
Sent: Thursday, June 25, 2020 9:25 AM
To: Susan Hares; 'Christian Huitema'; sec...@ietf.org
Cc: i2rs@ietf.org; draft-ietf-i2rs-yang-l2-network-topology....@ietf.org; 
last-c...@ietf.org
Subject: Re: [i2rs] Secdir last call review of 
draft-ietf-i2rs-yang-l2-network-topology-13

Sue and Christian:
I have responded to Christian on privacy issue, my proposal is to add MAC 
address as another data node vulnerability example in our original security 
consideration section.
But If Christian or security directorate has recommending text, we authors are 
happy to accept it.

-Qin
-----邮件原件-----
发件人: Susan Hares [mailto:sha...@ndzh.com] 
发送时间: 2020年6月25日 21:04
收件人: 'Christian Huitema' <huit...@huitema.net>; sec...@ietf.org
抄送: draft-ietf-i2rs-yang-l2-network-topology....@ietf.org; i2rs@ietf.org; 
last-c...@ietf.org
主题: RE: Secdir last call review of draft-ietf-i2rs-yang-l2-network-topology-13

Christian:

Thank you for catching the privacy issues.      

I've got a few questions to help the authors scope this change: 

1) Since this is common to all L2 Topologies, can you or the security 
directorate recommend some text that might be appropriate? 
   If you have recommended text, has this text been reviewed by OPS-DIR and 
Yang doctors? 

2) Will it be a problem If we write privacy considerations on IEEE 
specifications? 
3) Do we need to consider the range of deployments of L2 (home, enterprise,  
public PBB service, national PBB service, Data centers)


Thank you,  Sue 


-----Original Message-----
From: Christian Huitema via Datatracker [mailto:nore...@ietf.org]
Sent: Thursday, June 25, 2020 1:01 AM
To: sec...@ietf.org
Cc: draft-ietf-i2rs-yang-l2-network-topology....@ietf.org; i2rs@ietf.org; 
last-c...@ietf.org
Subject: Secdir last call review of draft-ietf-i2rs-yang-l2-network-topology-13

Reviewer: Christian Huitema
Review result: Has Issues

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 with the intent of improving security requirements and 
considerations in IETF drafts.  Comments not addressed in last call may be 
included in AD reviews during the IESG review.  Document editors and WG chairs 
should treat these comments just like any other last call comments.

This document describes a Yang model for representing Link Layer topologies.
Representing such topologies is obviously useful for managing network.
The security section is focused on securing the usage of this information for 
network management, but does not address potential privacy issues.

The security considerations explain correctly how altering the link layer 
information could enable attacks against the network. The proposed remedy is 
access control, implemented using either SSH or TLS. This is fine, although the 
discussion of TLS authorisation is a bit short. By default, TLS verifies the 
identity of the server but not that of the client. RFC8040 section 2.5 
specifies that "a RESTCONF server SHOULD require authentication based on TLS 
client certificates. I assume that's the intent, but it might be useful to say 
so.

On the other hand, the security considerations do not describe privacy issues, 
and I find that problematic. The proposed information model lists a number of 
sensitive data, such as for example the MAC addresses of devices.
This information can be misused. For example, applications could assess device 
location fetching the MAC addresses of local gateways. Third parties could 
access link local information to gather identities of devices accessing a 
particular network. Such information is often protected by privacy API in the 
Operating System, but accessing the Yang module over the network might allow 
applications to bypass these controls.

Client authentication alone does not necessarily protect against these privacy 
leaks. A classic configuration error would limit write access to authorized 
users, but to allow read-only access to most users. This kind of error would 
allow privacy leaks. Given the sensitive nature of MAC addresses and other 
identifiers, it is useful to warn against such errors.





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