Re: [mile] Stephen Farrell's Discuss on draft-ietf-mile-rfc5070-bis-22: (with DISCUSS and COMMENT)

[Kathleen Moriarty <[e-mail]>]

Hi Stephen,

Do the updates address your concerns?

Thanks!
Kathleen

On Mon, Jun 20, 2016 at 11:34 AM, Roman D. Danyliw <[e-mail]> wrote:
> Hi Stephen!
>
>> -----Original Message-----
>> From: Stephen Farrell [mailto:[e-mail]]
>> Sent: Thursday, June 02, 2016 11:54 AM
>> To: Roman D. Danyliw <[e-mail]>; The IESG <[e-mail]>
>> Cc: [e-mail]; [e-mail];
>> [e-mail]; [e-mail]; mile-
>> [e-mail]
>> Subject: Re: Stephen Farrell's Discuss on draft-ietf-mile-rfc5070-bis-22: (with
>> DISCUSS and COMMENT)
>>
>>
>> Hiya,
>>
>> On 02/06/16 04:36, Roman D. Danyliw wrote:
>> > Hello Stephen!
>> >
>> > Thanks for the review.  A response to the DISCUSS and COMMENTs is
>> > inline ...
>> >
>> >> -----Original Message----- From: Stephen Farrell
>> >> [mailto:[e-mail]] Sent: Wednesday, June 1, 2016
>> >> 7:42 PM To: The IESG <[e-mail]> Cc:
>> >> [e-mail]; Roman D. Danyliw
>> >> <[e-mail]>; [e-mail]; [e-mail];
>> >> [e-mail]; [e-mail]; [e-mail]
>> >> Subject: Stephen Farrell's Discuss on
>> >> draft-ietf-mile-rfc5070-bis-22: (with DISCUSS and COMMENT)
>> >
>> > [snip]
>> >
>> >> ----------------------------------------------------------------------
>> >>
>> >>
>> DISCUSS:
>> >> ----------------------------------------------------------------------
>> >>
>> >>
>> >>
>> (1) 3.6: Does one confidence value apply to all of these?
>> >> That seems wrong. And over-confidence is attributing threat actor
>> >> identity is a real issue with real consequences, hence the discuss
>> >> to make sure we bottom out on this. I think it's just too
>> >> error-prone to be ablve to associate one confidence value with two
>> >> things about which one can have very different concreteness. Mixing
>> >> up high confidence in a campaign with a lack of confidence in
>> >> threat actor identification is precisely the kind of thing that
>> >> goes wrong, or that could be deliberately manipulated (for
>> >> eventual media/marketing reasons). (This overlaps with but isn't
>> >> quite the same as Alissa's 2nd discuss point. In this case, I'm
>> >> explicitly worried about the threat actor identity confidence, as
>> >> that has possibly severe impacts, so the resolution here could
>> >> differ from what results from Alissa's discuss.)
>> >
>> > The RelatedActivity class (Section 3.6) does have the ability to
>> > provide a single confidence value on all of the child classes in it.
>> > Per your example, yes, a single confidence value could be made both
>> > on the campaign and the actor.  However, if more granularity was
>> > desired, one can express different confidence values for both the
>> > campaign and actor as follows (ThreatActor with low confidence but
>> > the Campaign with high confidence):
>> >
>> > <Incident ...> ... <RelatedActivity> <ThreatActor>...</ThreatActor>
>> > <Confidence rating="low" /> </RelatedActivity> <RelatedActivity>
>> > <Campaign>...</Campaign> <Confidence rating="high"/>
>> > </RelatedActivity> </Incident>
>>
>> Right, it's clear one can do the right thing, but it's not clear
>> what semantics apply when one does not do that. You could address
>> that in various ways, but I think in particular for the confidence/
>> threat-actor combination, the draft does need to say how to interpret
>> whatever the document contains.
>
> The following was added to the Security Considerations of -23 to explicitly call out that confidence assessment should not necessarily be trusted.
>
> 9.1.  Security
> [snip]
>    An IODEF implementation may act on the data in the document.  These
>    actions might be explicitly requested in the document or the result
>    of analytical logic that triggered on data in the document.  ...
>
>   The recipient may
>    interpret the contents of the document differently based on who sent
>    it; or vary actions based on the sender.  While the sender of the
>    document may explicitly convey confidence in the data in a granular
>    way using the Confidence class, the recipient is free to ignore or
>    refine this information to make its own assessment.
>
>    Certain classes may require out-of-band coordination to agree upon
>    their semantics (e.g., Confidence@rating="low" or DefinedCOA).  This
>    coordination MUST occur prior to operational data exchange to prevent
>    the incorrect interpretation of these select data elements.  When
>    parsing these data elements, implementations should validate, when
>    possible, that they conform to the agreed upon semantics.  These
>    semantics may need to be periodically reevaluated.
>
>> >> (2) 3.18.1 - you provide a way to specify e.g. an address and
>> >> netmask, or v6 prefix. But you don't specify any way to say that
>> >> some of the address (or prefix) bits are not real or are
>> >> additionally masked for privacy reasons. E.g. If everyone in
>> >> 2001:1:1:beef::/64 is misbehaving, but I don't (yet) want to
>> >> specify the exact prefix, I might want to say " some
>> >> 2001:1:1:xxxx::/64" is misbehaving, meaning one /64 in
>> >> 2001:1:1::/48 is being bad and not the entire /48. Why is support
>> >> for that not required?  (IPFIX does have that as an option, and
>> >> it's been added to CDNI too.) Same idea can apply to other address
>> >> forms too.
>> >
>> > Makes sense.  A few new Address@category enumerated value can be
>> > created, say "ipv6-net-sanitized" and "ipv4-net-sanitized" where "x"
>> > has the significance of masking bits in an otherwise valid
>> > address/prefix.
>>
>> So I think supporting something like that would be a good thing. If
>> the WG consider it but decide to not add it, I'll just clear.
>
> The following was added to -23 to provide comparable capability:
>
> 3.18.1.  Address Class
> [snip]
>       6.   ipv4-net-masked.  A sanitized IPv4 address with significant
>            bits per "ipv4-net" but with the character 'x' replacing any
>            digit(s) in the address or prefix.
> [snip]
>       10.  ipv6-net-masked.  A sanitized IPv6 address and prefix per
>            "ipv6-net" but with the character 'x' replacing any
>            hexadecimal digit(s) in the address or digit(s) in the
>            prefix.
>
>> >> ----------------------------------------------------------------------
>> >>
>> >>
>> COMMENT:
>> >> ----------------------------------------------------------------------
>> >>
>> >>
>> >>
>> >>
>> - My review is based on [1]
>> >> [1]
>> >> https://tools.ietf.org/rfcdiff?url1=rfc5070&url2=draft-ietf-mile-rfc5070-
>> bis-22
>> >>
>> >>
>> >>
>> - "cyber" galore - yuk! Which of the fourteen (14!) uses of that ill-defined
>> >> marketing term are useful or even well defined?  RFC5070 had zero
>> >> uses of such terms. Why is it a good plan for us to damage the RFC
>> >> series via the use of such marketing nonsense? Someone may answer
>> >> that this is accepted in industry these days, and that is true, but
>> >> is nonetheless not a good enough reason for us to assist with the
>> >> promulgation of anti-scientific non-concepts. My suggestion is to
>> >> try s/cyber//g and then to see what if anything is less clear -
>> >> perhaps we'll find that things are more clear. (And yes, it's a bit
>> >> of a bugbear of mine:-) The use of "cyber indicator" instead of
>> >> just "indicator" in 3.19 is a good example of how that phrase makes
>> >> the spec less clear.
>> >
>> > Alissa commented on the same thing.  Please see my response there
>> > (https://www.ietf.org/mail-archive/web/mile/current/msg01886.html).
>> > Long story short, IMO, there are a few instances where cyber is the
>> > appropriate adjective (e.g., a "cyber-physical system").
>
> This was cleaned up in -23.
>
> [snip]
>
>> >> - 2.8: So you don't like leap-seconds? It's often good to be clear
>> >> if that bit of ABNF is expected to be enforced along with schema
>> >> validation or not.
>> >
>> > As currently specified, if the schema is validated, this regex will
>> > be enforced.  It's baked into the schema with the iodef:TimezoneType.
>> > Whether the schema should be validated is a separate issue that you
>> > also brought up in another COMMENT (see below).
>>
>> That's fine - what about leap seconds?
>
> The regex in -23 was updated to be:
>
>     <xs:simpleType name="TimezoneType">
>       <xs:restriction base="xs:string">
>         <xs:pattern
>          value="Z|[\+\-](0[0-9]|1[0-4]):[0-5][0-9](:[0-5][0-9])?"/>
>
>>
>> The rest below is fine,
>> Cheers,
>> S.
>>
>> >
>> >> - 2.12: What about EAI?
>> >
>> > Good point.  I'll change the reference to RFC5336.
>
> The text in -23 now reads:
>
> 2.12.  Email String
>
>    An email address is represented in the information model by the EMAIL
>    data type.  The format of the EMAIL data type is documented in
>    Section 3.4.1 of [RFC5322] and Section 3.3 of [RFC6531].
>
>> >> - 3.13.1 - is CoA expanded somewhere? (See, I just looked at the
>> >> diff:-)
>> >
>> > The write-up of the class in 3.13.1 says "DefinedCOA = Zero or more.
>> > STRING.  An identifier meaningful to the sender and recipient of this
>> > document that references a course of action."  I can make that
>> > clearer by saying "... references a course of action (COA)".
>
> The text in -23 now reads:
>
>    DefinedCOA
>       Zero or more.  STRING.  An identifier meaningful to the sender and
>       recipient of this document that references a course of action
>       (COA).  This class MUST be present if the action attribute is set
>       to "defined-coa".
>
>> >> - 3.18.1 - I think it'd be good to refer to the RFC for wriing down
>> >> IPv6 addresses and prefixes. I forget it's number though:-) And who
>> >> uses ipv6- net-mask? Don't we all use prefixes?
>
> The text in -23 now reads:
>
>       8.   ipv6-addr.  IPv6 host address per Section 4 of [RFC5952].
>
>       9.   ipv6-net.  IPv6 network address, slash, prefix per
>            Section 2.3 of [RFC4291].
>
>> > Ipv6-net-mask is a hold over form rfc5070.  I'll find the right
>> > reference and drop it here.
>
> Yes, it was a cut-and-paste from RFC5070.  Address@type="ipv6-net-mask" is now removed.
>
> [snip]
>
>> >> - 4.3 - I also think that recommending schema validation of input
>> >> documents is a bad plan. (Even if that was already in 5070.)
>
> Schema validation is now just RECOMMENDED per -23.  A full discussion as it relates to the security review is at:
>
> https://mailarchive.ietf.org/arch/msg/mile/cz8_ZoyVYZX88QUoqeEgZQFUrYE
>
> https://mailarchive.ietf.org/arch/msg/mile/uPHPtq_PvUvxKTP4jKA5x6_y2Jg
>
>> > Robert Sparks security review
>> > (https://www.ietf.org/mail-archive/web/mile/current/msg01869.html)
>> > and Alexey's review hinted at this issue but in the context of
>> > dynamically generated schemas.  I'll start the conversation on this
>> > issue on that thread.
>
> The discussion and changes made in -23 to address the concerns with dynamically generated schemas can be found at:
>
> https://mailarchive.ietf.org/arch/msg/mile/cz8_ZoyVYZX88QUoqeEgZQFUrYE
>
> [snip]
>
>> >> - 9.1: you could not here the DoS and possible other attacks (e.g.
>> >> spoofed .xsd files loaded over port 80) that follow on from on-line
>> >> schema
>> >
>> > Good point.  If the underlying schema is to be dynamically generated,
>> > there is an IANA-to-schema-generator channel to secure that should be
>> > covered here.  This will need new text, the substance of which will
>> > depend on the clarifying conversation that needs to happen on how
>> > these dynamic updates should be handled.
>
> These is addressed in the links to the security review in the previous item.
>
> [snip]
>
> Thank you for the detailed review.
>
> Roman
>



-- 

Best regards,
Kathleen