Security Requirements of Time Protocols in Packet Switched Networks
draft-ietf-tictoc-security-requirements-12

[Ballot comment]
Thanks for addressing the SecDir review.

I just have a question on the Confidentiality (5.8) part of the Security Considerations section, it says:

"Requirement Level

  The requirement level of this requirement is 'MAY' since it does not
  prevent severe threats, as discussed below."

That reads a bit oddly to me and I am wondering if there is a typo, maybe presents instead of prevents?

[Ballot comment]


- 2.4: defining e2e security as just meaning data integrity
without confidentiality is unusual enough that it should
probably be noted. Separately I'm surprised that you don't
include some form of origin authentication in your concept
of e2e security - why is that?

- 3.2: possible threat - ensure specific client(s) offset by
X (different X for each set you need to track) in order to
spot (or reduce search space for) those clients in other
protocols when timestamp are sent. Worth adding?  I'm not
sure if a mechanisms meeting the 5.9 requirement would or
would not be sure to mitigate this. (You could also advise
protocols emitting timing information to slighly perturb any
time signals they emit, to disguise any small but detectable
offset from the wall-clock time.)

- 3.2: another possible threat: if a mobile node sends time
protocol requests at a specific frequency (e.g.  every N
seconds, at 283 ms past the second) then that can be used to
identify (or reduce the search space for) the mobile node
irrespective of crypto or address changes. (A similar thing
has been a real concern in vehicular networks btw. with the
basic safety message).  Those are probably not that big a
deal here and the migitation is probably just to tell
implementers to not do that, which is pretty simple:-)

- 3.2 - Similarly, if a node sends out complex time protocol
messages those might allow fingerprinting of the node
regardless of other changes. For example, it could be easy
to track a Brazilian node that's in Europe if it sends
queries out saying it mostly trusts something in .br.  Not
sure if that's as easy to deal with, perhaps the requirement
there is just that protocol developers think about it. (This
relates to Kathleen's discuss also probably.)

- 5.6.1: that requirement is stated as an operational
requirement, don't you need a protocol requirement here i.e.
to say that it MUST be possible to ensure keys are fresh?

- 5.10 - I wonder if there's not a case to be made for an
opportunistic mode, e.g. where one learns that some master
can be authenticated and thereafter requires that. In this
document I think such an opportunistic mode would maybe be a
MAY - the WG can think later if they figure that'd help
enough to be worthwhile. The reason to raise it now is thus
so as to not rule it out for later. I think this is
different from, and possibly much better than the hybrid
thing you have now and ought be much more deployable than a
"secure" mode (as in 5.10.1, and that's a bad term for that
section/mode btw).

- 7.5: Kerberos is notoriously more time-sensitive than PKI
stuff - why not mention it?

[Ballot discuss]
The draft looks very good, thanks for your work on it and for addressing the SecDir review!

I just have some questions on the Confidentiality section (5.8) here and in a comment below.

We discussed a scenario two weeks ago (I think) in relation to a time protocol, where privacy questions/concerns were raised (I think by Spencer).  Since time information could be tied to locality, time zones, etc., the queries could give away information about an individual's schedule, patterns, etc.  This seems to apply here as well and if so, raises the profile for the requirement for confidentiality to better cover privacy concern, right?  If it doesn't apply, just let me know, but figured it was worth checking.  I think just mentioning it as an example would suffice since ther ewill be cases where confidentiality does not matter.

[Ballot discuss]
The draft looks very good, thanks for your work on it and for addressing the SecDir review!

I just have some questions on the Confidentiality section (5.8) here and in a comment below.

We discussed a scenario two weeks ago (I think) in relation to a time protocol, where privacy questions/concerns were raised (I think by Spencer).  Since time information could be tied to locality, time zones, etc., the queries could give away information about an individual's schedule, patterns, etc.  This seems to apply here as well and if so, raises the profile for the requirement for confidentiality to better cover privacy concern, right?  If it doesn't apply, just let me know, but figured it was worth checking.

[Ballot comment]
Thanks for addressing the SecDir review.

I just have a question on the Confidentiality part of the Security Considerations section, it says:

"Requirement Level

  The requirement level of this requirement is 'MAY' since it does not
  prevent severe threats, as discussed below."

That reads a bit oddly to me and I am wondering if there is a typo, maybe presents instead of prevents?

[Ballot comment]
neither 3.2.7 nor 3.2.2 3.2.4 or 5.3 describe actual dos attacks using the ntp protocol.

Those do involve spoofing client source address (of the victim) but rely on nothing other an asymmetry in the size of the response relative to the query.

[Ballot comment]
I think Barry is likely correct about the time protocols themselves being normative references.

This document was a pleasure to review - very clear and well-organized for One Unskilled In The Art ...

As required by RFC 4858, this is the current template for the Document
Shepherd Write-Up.

Changes are expected over time. This version is dated 24 February 2012.

(1) What type of RFC is being requested (BCP, Proposed Standard, Internet Standard,
Informational, Experimental, or Historic)? Why is this the proper type of RFC? Is this type
of RFC indicated in the title page header?

An Informational RFC is being requested because this document specifies requirements
and considerations for requirements on time synchronization protocols. As such, it is
intended to guide future work.

(2) The IESG approval announcement includes a Document Announcement Write-Up.
Please provide such a Document Announcement Write-Up. Recent examples can be
found in the "Action" announcements for approved documents. The approval
announcement contains the following sections:

Technical Summary:

As time and frequency distribution protocols are becoming increasingly common and
widely deployed, concern about their exposure to various security threats is increasing.
This document defines a set of security requirements for time protocols, focusing on the
Precision Time Protocol (PTP) and the Network Time Protocol (NTP). This document also
discusses the security impacts of time protocol practices, the performance implications of
external security practices on time protocols and the dependencies between other
security services and time synchronization.

Working Group Summary:

This document has been around for a long time. It has been socialized outside the IETF
community and is currently being used as the basis of the security work ongoing in the
IEEE 1588 community.

Document Quality:

This is a requirements document and as such doesn’t have implementations. The
document has received several reviews in various communities.

Personnel:

Karen O’Donoghue is the document shepherd.
Brian Haberman is the responsible area director.

(3) Briefly describe the review of this document that was performed by the Document
Shepherd. If this version of the document is not ready for publication, please explain why
the document is being forwarded to the IESG.

The document shepherd has reviewed all versions of this document and believes that it is
ready for publication.

(4) Does the document Shepherd have any concerns about the depth or breadth of the
reviews that have been performed?

The document shepherd has no concerns regarding the reviews performed on the
document.

(5) Do portions of the document need review from a particular or from broader
perspective, e.g., security, operational complexity, AAA, DNS, DHCP, XML, or
internationalization? If so, describe the review that took place.

Given that the document specifies security requirements, comments from the security
community during the broader IETF review process would be helpful. However,
comments have been solicited over time.

(6) Describe any specific concerns or issues that the Document Shepherd has with this
document that the Responsible Area Director and/or the IESG should be aware of? For
example, perhaps he or she is uncomfortable with certain parts of the document, or has
concerns whether there really is a need for it. In any event, if the WG has discussed those
issues and has indicated that it still wishes to advance the document, detail those
concerns here.

The document shepherd has no specific concerns or issues with this document.

(7) Has each author confirmed that any and all appropriate IPR disclosures required for
full conformance with the provisions of BCP 78 and BCP 79 have already been filed. If
not, explain why?

As a requirements document, IPR disclosures are not an issue.

(8) Has an IPR disclosure been filed that references this document? If so, summarize any
WG discussion and conclusion regarding the IPR disclosures.

No IPR disclosures have been filed with respect to this document.

(9) How solid is the WG consensus behind this document? Does it represent the strong
concurrence of a few individuals, with others being silent, or does the WG as a whole
understand and agree with it?

There is solid WG consensus on this document.

(10) Has anyone threatened an appeal or otherwise indicated extreme discontent? If so,
please summarise the areas of conflict in separate email messages to the Responsible
Area Director. (It should be in a separate email because this questionnaire is publicly
available.)

There have been no threats of appeal or extreme discontent with this document.

(11) Identify any ID nits the Document Shepherd has found in this document. (See
http://www.ietf.org/tools/idnits/ and the Internet-Drafts Checklist). Boilerplate checks are
not enough; this check needs to be thorough.

There are no ID nits in this document.

(12) Describe how the document meets any required formal review criteria, such as the
MIB Doctor, media type, and URI type reviews.

There are no formal review criteria for this document.

(13) Have all references within this document been identified as either normative or
informative?

All references are identified as normative or informative.

(14) Are there normative references to documents that are not ready for advancement or
are otherwise in an unclear state? If such normative references exist, what is the plan for
their completion?

There are no normative references in an unclear state.

(15) Are there downward normative references references (see RFC 3967)? If so, list
these downward references to support the Area Director in the Last Call procedure.

There are no downward normative references.

(16) Will publication of this document change the status of any existing RFCs? Are those
RFCs listed on the title page header, listed in the abstract, and discussed in the
introduction? If the RFCs are not listed in the Abstract and Introduction, explain why, and
point to the part of the document where the relationship of this document to the other
RFCs is discussed. If this information is not in the document, explain why the WG
considers it unnecessary.

This document does not have any impact on any existing RFC.

(17) Describe the Document Shepherd's review of the IANA considerations section,
especially with regard to its consistency with the body of the document. Confirm that all
protocol extensions that the document makes are associated with the appropriate
reservations in IANA registries. Confirm that any referenced IANA registries have been
clearly identified. Confirm that newly created IANA registries include a detailed
specification of the initial contents for the registry, that allocations procedures for future
registrations are defined, and a reasonable name for the new registry has been
suggested (see RFC 5226).

This document doesn’t specify any IANA registries.

(18) List any new IANA registries that require Expert Review for future allocations.
Provide any public guidance that the IESG would find useful in selecting the IANA Experts
for these new registries.

This document doesn’t specify any IANA registries.

(19) Describe reviews and automated checks performed by the Document Shepherd to
validate sections of the document written in a formal language, such as XML code, BNF
rules, MIB definitions, etc.

There are no formal language sections of this document. 

IESG/Authors/WG Chairs:

IANA has reviewed draft-ietf-tictoc-security-requirements-10, which is currently in Last Call, and has the following comments:

We understand that this document doesn't require any IANA actions.

While it is helpful for the IANA Considerations section of the document to remain in place upon publication, if the authors prefer to remove it, IANA doesn't object.

If this assessment is not accurate, please respond as soon as possible.

The following Last Call announcement was sent out:

From: The IESG
To: IETF-Announce
CC:
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Security Requirements of Time Protocols in Packet Switched Networks) to Informational RFC


The IESG has received a request from the Timing over IP Connection and
Transfer of Clock WG (tictoc) to consider the following document:
- 'Security Requirements of Time Protocols in Packet Switched Networks'
  as Informational RFC

The IESG plans to make a decision in the next few weeks, and solicits
final comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2014-07-16. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the
beginning of the Subject line to allow automated sorting.

Abstract


  As time and frequency distribution protocols are becoming
  increasingly common and widely deployed, concern about their exposure
  to various security threats is increasing. This document defines a
  set of security requirements for time protocols, focusing on the
  Precision Time Protocol (PTP) and the Network Time Protocol (NTP).
  This document also discusses the security impacts of time protocol
  practices, the performance implications of external security
  practices on time protocols and the dependencies between other
  security services and time synchronization.




The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-tictoc-security-requirements/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-tictoc-security-requirements/ballot/


No IPR declarations have been submitted directly on this I-D.

As required by RFC 4858, this is the current template for the Document
Shepherd Write-Up.

Changes are expected over time. This version is dated 24 February 2012.

(1) What type of RFC is being requested (BCP, Proposed Standard, Internet Standard, Informational, Experimental, or Historic)? Why is this the proper type of RFC? Is this type of RFC indicated in the title page header?

An Informational RFC is being requested because this document specifies requirements and considerations for requirements on time synchronization protocols. As such, it is intended to guide future work.

(2) The IESG approval announcement includes a Document Announcement Write-Up. Please provide such a Document Announcement Write-Up. Recent examples can be found in the "Action" announcements for approved documents. The approval announcement contains the following sections:

Technical Summary:

As time and frequency distribution protocols are becoming increasingly common and widely deployed, concern about their exposure to various security threats is increasing. This document defines a set of security requirements for time protocols, focusing on the Precision Time Protocol (PTP) and the Network Time Protocol (NTP). This document also discusses the security impacts of time protocol practices, the performance implications of external security practices on time protocols and the dependencies between other security services and time synchronization.

Working Group Summary:

This document has been around for a long time. It has been socialized outside the IETF community and is currently being used as the basis of the security work ongoing in the IEEE 1588 community.

Document Quality:

This is a requirements document and as such doesn’t have implementations. The document has received several reviews in various communities.

Personnel:

Karen O’Donoghue is the document shepherd, and Brian Haberman is the responsible area director.

(3) Briefly describe the review of this document that was performed by the Document Shepherd. If this version of the document is not ready for publication, please explain why the document is being forwarded to the IESG.

The document shepherd has reviewed all versions of this document and believes that it is ready for publication.

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews that have been performed?

The document shepherd has no concerns regarding the reviews performed on the document.

(5) Do portions of the document need review from a particular or from broader perspective, e.g., security, operational complexity, AAA, DNS, DHCP, XML, or internationalization? If so, describe the review that took place.

Given that the document specifies security requirements, comments from the security community during the broader IETF review process would be helpful. However, comments have been solicited over time.

(6) Describe any specific concerns or issues that the Document Shepherd has with this document that the Responsible Area Director and/or the IESG should be aware of? For example, perhaps he or she is uncomfortable with certain parts of the document, or has concerns whether there really is a need for it. In any event, if the WG has discussed those issues and has indicated that it still wishes to advance the document, detail those concerns here.

The document shepherd has no specific concerns or issues with this document.

(7) Has each author confirmed that any and all appropriate IPR disclosures required for full conformance with the provisions of BCP 78 and BCP 79 have already been filed. If not, explain why?

As a requirements document, IPR disclosures are not an issue.

(8) Has an IPR disclosure been filed that references this document? If so, summarize any WG discussion and conclusion regarding the IPR disclosures.

No IPR disclosures have been filed with respect to this document.

(9) How solid is the WG consensus behind this document? Does it represent the strong concurrence of a few individuals, with others being silent, or does the WG as a whole understand and agree with it?

There is solid WG consensus on this document.

(10) Has anyone threatened an appeal or otherwise indicated extreme discontent? If so, please summarise the areas of conflict in separate email messages to the Responsible Area Director. (It should be in a separate email because this questionnaire is publicly available.)

There have been no threats of appeal or extreme discontent with this document.

(11) Identify any ID nits the Document Shepherd has found in this document. (See http://www.ietf.org/tools/idnits/ and the Internet-Drafts Checklist). Boilerplate checks are not enough; this check needs to be thorough.

There are no ID nits in this document.

(12) Describe how the document meets any required formal review criteria, such as the MIB Doctor, media type, and URI type reviews.

There are no formal review criteria for this document.

(13) Have all references within this document been identified as either normative or informative?

All references are identified as normative or informative.

(14) Are there normative references to documents that are not ready for advancement or are otherwise in an unclear state? If such normative references exist, what is the plan for their completion?

There are no normative references in an unclear state.

(15) Are there downward normative references references (see RFC 3967)? If so, list these downward references to support the Area Director in the Last Call procedure.

There are no downward normative references.

(16) Will publication of this document change the status of any existing RFCs? Are those RFCs listed on the title page header, listed in the abstract, and discussed in the introduction? If the RFCs are not listed in the Abstract and Introduction, explain why, and point to the part of the document where the relationship of this document to the other RFCs is discussed. If this information is not in the document, explain why the WG considers it unnecessary.

This document does not have any impact on any existing RFC.

(17) Describe the Document Shepherd's review of the IANA considerations section, especially with regard to its consistency with the body of the document. Confirm that all protocol extensions that the document makes are associated with the appropriate reservations in IANA registries. Confirm that any referenced IANA registries have been clearly identified. Confirm that newly created IANA registries include a detailed specification of the initial contents for the registry, that allocations procedures for future registrations are defined, and a reasonable name for the new registry has been suggested (see RFC 5226).

This document doesn’t specify any IANA registries.

(18) List any new IANA registries that require Expert Review for future allocations. Provide any public guidance that the IESG would find useful in selecting the IANA Experts for these new registries.

This document doesn’t specify any IANA registries.

(19) Describe reviews and automated checks performed by the Document Shepherd to validate sections of the document written in a formal language, such as XML code, BNF rules, MIB definitions, etc.

There are no formal language sections of this document.