Re: [Dots] AD evaluation of draft-ietf-dots-use-cases-20

["Teague, Francis" <[e-mail]>]

Hi,

Volumetry is awkward - generally an attack is characterized as
volumetric so volume would be correct IMO.

On the BGP side - My 2c - There are methods such as RPKI etc. which present
concerns for BGP based mitigations where implemented, however, these may be
overcome in a number of ways (the mitigator being authorized to originate
prefixes using the customer ASN for example during an attack).  The methods
used to overcome these challenges while remaining compliant with a
particular mechanism are really between the requestor and mitigator to
thrash out.  I'm not sure we should call it out as its part of the wider
relationship/onboarding process.  It's probably a topic for its own BCP
though.

Thanks,

-Nik

On Wed, 13 May 2020 at 17:07, Daniel Migault <[e-mail]> wrote:

> Hi,
>
> Thank you Ben for you comments. Please find inline how these have been
> addressed. The updated version has been pushed to [1].
>
> The main questions I have for the co-authors are:
> * does the change of volumetry to volume causes any concern ?
> * I guess we could be a little be more specific regarding the delegation
> and the pre-arrangement, in particular if BGP is secured. Please update
> the text that has been proposed.
>
> Yours,
> Daniel
>
>
> [1] https://github.com/dotswg/dots-use-cases
>
> On Tue, May 12, 2020 at 4:22 PM Benjamin Kaduk <[e-mail]> wrote:
>
>> Hi all,
>>
>> This one is in pretty good shape -- I don't have any major comments on it.
>> I did write up some editorial nit-level stuff as a github pull request:
>> https://github.com/dotswg/dots-use-cases/pull/12 .  I think that nothing
>> there should be controversial, but please let me know if I am wrong about
>> that.
>>
>> Please confirm that all six authors made significant contributions: I
>> will need to defend this to the rest of the IESG, since per RFC 7322 the
>> author count is generally limited to five individuals.  Right now I don't
>> have a good response when someone asks.
>>
>
> <mglt>
> As far as I know all authors mentioned significantly contributed to the
> document. It is true that there are many co-authors, but I think that
> reflected that DOTS needs to coordinate multiple actors that were not so
> much coordinated before.
> </mglt>
>
>>
>> Section 1
>>
>>    As DDoS solutions are broadly heterogeneous among vendors, the
>>    primary goal of DOTS is to provide high-level interaction amongst
>>    differing DDoS solutions, such as detecting, initiating, terminating
>>    DDoS mitigation assistance or requesting the status of a DDoS
>>    mitigation.
>>
>> nit: the list structure is not properly parallel.  It looks like the
>> various clauses are meant to be "detecting DDoS",
>> "initiating/terminating mitigation assistance", and "requesting
>> mitigation status", so maybe this could become:
>>
>> % As DDoS solutions are broadly heterogeneous among vendors, the
>> % primary goal of DOTS is to provide high-level interaction amongst
>> % differing DDoS solutions, such as detecting DDoS attacks,
>> % initiating/terminating DDoS mitigation assistance, or requesting the
>> % status of a DDoS mitigation.
>>
>> <mglt>
> fixed
> </mglt>
>
>> Section 3.1
>>
>>    Over the course of the attack, the DOTS server of the ITP
>>    periodically informs the DOTS client on the enterprise DMS mitigation
>>    status, statistics related to DDoS attack traffic mitigation, and
>>    related information.  Once the DDoS attack has ended, or decreased to
>>    the certain level that the enterprise DMS can handle by itself, the
>>    DOTS server signals the enterprise DMS DOTS client that the attack
>>    has subsided.
>>
>> It's interesting that this is worded in such a way that the (ITP) DOTS
>> server knows the specific threshold for what level of attack traffic the
>> enterprise DMS can handle, since it's the DOTS server signalling to the
>> client that "the attack has subsided".
>>
>> <mglt>
> In most cases, if I recall correctly, we expect this to reflect a
> contractual relation. That said, it is ultimately the DOTS client that
> terminates the mitigation. To remove the impression that the ITP sort of
> controls the DOTS client, I propose to change "can handle" by "may
> handle".  Here is the updated text:
>
> Once the DDoS attack has ended, or decreased to the certain
> level that the enterprise DMS may handle by itself, the DOTS server
> signals the enterprise DMS DOTS client that the attack has subsided.
> </mglt>
>
> Section 3.3
>>
>>    Upon receipt of the DOTS mitigation request from the DDoS telemetry
>>    system, the orchestrator DOTS server responds with an acknowledgment,
>>    to avoid retransmission of the request for mitigation.  The
>>    orchestrator may begin collecting additional fine-grained and
>>    specific information from various DDoS telemetry systems in order to
>>    correlate the measurements and provide an analysis of the event.
>>    Eventually, the orchestrator may ask for additional information from
>>    the DDoS telemetry system; however, the collection of this
>>    information is out of scope.
>>
>> The last sentence seems to say that how the orchestrator gets data from
>> the initial DOTS client telemtry system is out-of-scope, but the
>> previous sentence talks about the orchestrator collecting information
>> from (other) DOTS telemetry systems.  Is that similarly out of scope?
>> If so, then the fact that they are specifically *DOTS* telemetry systems
>> seems irrelevant and we should probably just describe them as generic
>> telemetry or monitoring systems.
>>
>> <mglt>
> I agree that we should not have DOTS telemetry systems and leave them as
> DDoS telemetry systems. I checked the current version and there is no
> mention of DOTS telemetry but only DDoS telemetry.
> I also suggest the we specify that such collection is out of scope of
> DOTS. with the following sentence:
>
> the collection of this information is out of scope of DOTS.
> </mglt>
>
>
>>    Upon receiving a request to mitigate a DDoS attack performed over a
>>    target, the orchestrator may evaluate the volumetry of the attack as
>>
>> nit(?): is "performed over" a conventional usage?  I would have expected
>> something more like "aimed at" given my personal background, but could
>> just be ignorant of typical usage.
>>
> <mglt>
> changed.
> </mglt>
>
>>
>> Also, I think "volumetry" is not the right word here, and just "volume"
>> suffices.
>>
> <mglt>
> I am fine either way. The current version changed to volume, but I am
> waiting co-authors to confirm they agree with the change.
> </mglt>
>
>>
>>    filter the traffic.  In this case, the DDoS mitigation system
>>    implements a DOTS client while the orchestrator implements a DOTS
>>    server.  Similar to other DOTS use cases, the offloading scenario
>>    assumes that some validation checks are followed by the DMS, the
>>    orchestrator, or both (e.g., avoid exhausting the resources of the
>>    forwarding nodes or disrupting the service).  These validation checks
>>    are part of the mitigation, and are therefore out of the scope of the
>>    document.
>>
>> I know we added this last chunk of text after a long exchange during the
>> last WGLC, and understand the desire to avoid going into too many
>> details on a topic that is mostly out of scope for DOTS.  That said, I'd
>> suggest adding a couple more words around "disrupting the service"
>> (especially since some level of service disruption during an attack
>> might be expected!) to help the reader make the link to what kind of
>> validation is expected, perhaps something like "inadvertent disruption
>> of legitimate services".
>>
>> <mglt>
> fixed with the follwoing snetence:
>
> Similar to other DOTS use cases, the offloading scenario assumes that some
> validation checks are followed by the DMS, the orchestrator, or both (e.g.,
> avoid exhausting the resources of the forwarding nodes or inadvertent
> disruption of legitimate services).
> </mglt>
>
>> Section 4
>>
>> In light of my previous comment I don't want to go too far here, but I
>> could see it being relevant to have a note that in the "orchestration"
>> case it's possible for something that locally to one telemetry system
>> looks like an attack is not actually an attack when seen from the
>> broader scope (e.g., of the orchestrator).
>>
>> <mglt>
> I added the note in the following paragraph.
>
> These systems are configured so that when an event or some measurement
> indicators reach a predefined level their associated DOTS client sends a
> DOTS mitigation request to the orchestrator DOTS server. The DOTS
> mitigation request may be associated with some optional mitigation hints
> to let the orchestrator know what has triggered the request. In
> particular, it's possible for something that locally to one telemetry
> system looks like an attack is not actually an attack when seen from the
> broader scope (e.g., of the orchestrator)
> </mglt>
>
> In the Third Party MSP case we mention BGP as a way to steer traffic to
>> the mitigation service.  We could consider (but don't have to)
>> mentioning that efforts to secure BGP will need to be considered when
>> making pre-arrangements for how traffic is to be moved, since in some
>> contexts such BGP announcements could themselves be considered to be an
>> attack.
>>
>> <mglt>
> Being ignorant on BGP, I am wondering if you are thinking of a BGP
> procedure to announce routes or some procedure for enabling a delegation
> when BGPsec is considered.
> I porpose the following text:
>
> These exact mechanisms
> used for traffic steering are out of scope of DOTS, but will need to be
> pre-arranged, while in some context such changed could be detected and
> considered as an attack.
>
> </mglt>
>
>> I guess it probably goes without saying that when you add a third-party
>> DMS to your setup, you depend on that third party to be operational in
>> order for your setup to work properly.
>>
>> Section 7
>>
>> We'll probably get someone asking to move RFC 8612 to be a Normative
>> reference since we use it for terminology, but I don't mind leaving it
>> be for now.
>>
>
> <mglt>
> I put it as normative.
> </mglt>
>
>>
>> Thanks,
>>
>> Ben
>>
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>>
>
>
> --
> Daniel Migault
> Ericsson
>

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