DOTS Y. Hayashi, Ed.
Internet-Draft NTT
Intended status: Informational K. Nishizuka, Ed.
Expires: September 9, 2019 NTT Communications
M. Boucadair, Ed.
Orange
March 8, 2019
DDoS Mitigation Offload: A DOTS Applicability Use Case
draft-hayashi-dots-dms-offload-usecase-00
Abstract
This document describes the applicability of DOTS to a DDoS
mitigation offload use case. This use case assumes that a DMS (DDoS
Mitigation System) whose utilization rate is high sends its blocked
traffic information to an orchestrator using DOTS protocols, then the
orchestrator requests forwarding nodes such as routers to filter the
traffic. Doing so enables service providers to mitigate DDoS attack
traffic automatically while ensuring interoperability and distributed
filter enforcement.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. The Problem . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. DOTS Applicability to DDoS Mitigation Offload Use Case . . . 3
4.1. Component and Sequence Diagram . . . . . . . . . . . . . 3
4.2. Case: DOTS Request via Out-of-band Link . . . . . . . . . 5
4.3. Case: Mitigation Request via In-band Link . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . 7
8.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
Volume-based distributed denial-of-service (DDoS) attacks such as DNS
amplification attacks are critical threats to be handled by service
providers. When such attacks occur, service providers have to
mitigate them immediately to protect or recover their services.
Therefore, for the service providers to immediately protect their
network services from DDoS attacks, DDoS mitigation needs to be
automated. To automate DDoS attack mitigation, it is desirable that
multi-vendor elements involved in DDoS attack detection and
mitigation collaborate and support standard interfaces to
communicate.
DDoS Open Threat Signaling (DOTS) is a set of protocols for real-time
signaling, threat-handling requests, and data between the multi-
vendor elements [I-D.ietf-dots-signal-channel]
[I-D.ietf-dots-data-channel]. This document describes an automated
DDoS Mitigation offload use case inherited from the DDoS
orchestration use case [I-D.ietf-dots-use-cases], which ambitions to
enable cost-effective DDoS Mitigation.
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2. Terminology
The readers should be familiar with the terms defined in
[I-D.ietf-dots-requirements] [I-D.ietf-dots-use-cases]
In addition, this document uses the terms defined below:
Mitigation offload: Getting rid of a DMS's mitigation action and
assigning the action to another entity when the utilization rate
of the DMS reaches a given threshold. How such threshold is set
is deployment-specific.
Utilization rate: A scale to measure load of an entity such as link
utilization rate or CPU utilization rate.
3. The Problem
In general, DDoS countermeasures are divided into detection and
filtering, and detection is technically difficult. DDoS Mitigation
System (DMS) can detect attack traffic based on the technology of
their vendors, so service providers can increase DDoS countermeasure
level by deploying the DMS in their network.
However, the number/capacity of DMS instances that can be deployed in
a service providers network is limited due to equipment cost and
dimensioning matters. Thus, DMS's utilization rate can reach its
maximum capacity faster when the volume of DDoS attacks is enormous.
When the rate reaches maximum capacity, the mitigation strategy needs
to offload mitigation actions from the DMS to cost-effective
forwarding nodes such as routers.
4. DOTS Applicability to DDoS Mitigation Offload Use Case
This section does not consider deployments where the network
orchestrator and DMS are co-located.
4.1. Component and Sequence Diagram
Figures 1 and 2 show a component diagram and a sequence diagram of
the use case, respectively.
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+--------------+ +-----------+
| | | DDoS |+
| Orchestrator |<-------| mitigation||
| |S DOTS C| systems ||
+--------------+ +-----------+|
| +----------+
| e.g., BGP, BGP Flowspec
|
| +------------------+
+->| Forwarding nodes |+
+------------------+|
+-----------------+
* C is for DOTS Client function
* S is for DOTS Server function
Figure 1: Component Diagram of DDoS Mitigation Offload Use Case
The component diagram shown in Figure 1 differs from that of DDoS
Orchestration usecase in [I-D.ietf-dots-use-cases] in some respects.
First, the DMS embeds a DOTS client to send DOTS requests to the
orchestrator. Second, the orchestrator sends a request to underlying
forwarding nodes to filter the attack traffic.
+------------+ +----------+ +------------+
| | |DDoS |+ | Forwarding |+
|Orchestrator| |Mitigation|| | Nodes ||
| | |Systems || | ||
+------------+ +----------+| +------------+|
| +----------+ +------------+
| | |
| DOTS Request | |
|S<----------------------C| |
| | |
| e.g., BGP, BGP Flowspec | |
| Filter Attack Traffic | |
|-------------------------|------------->|
| | |
* C is for DOTS Client function
* S is for DOTS Server function
Figure 2: Sequence Diagram of DDoS Mitigation Offload Use Case
In this use case, it is assumed that volume based attack already hits
a network and attack traffic is detected and blocked by a DMS in the
network. When the volume-based attack becomes intense, DMS's
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utilization rate can reach a certain threshold (e.g., maximum
capacity). Then, the DMS sends a DOTS request as offload request to
the orchestrator with the actions to enforce on the traffic. After
that, the orchestrator requests the forwarding nodes to filter attack
traffic by dissemination of flow specification rules protocols such
as BGP Flowspec [RFC5575] on the basis of the blocked traffic
information.
This use case is divided into two cases as discussed below. One is
that the DMS sends DOTS requests to the orchestrator via out-of-band
link, and the other one is that the DMS sends it via in-band link.
4.2. Case: DOTS Request via Out-of-band Link
In this case, the DMS sends a DOTS request to the orchestrator with
information of blocked traffic information by the DMS via out-of-band
link. The link is not congested when it is under volume attack-time,
so DOTS data channel [I-D.ietf-dots-data-channel] is suitable because
DOTS data channel has capability of conveying the drop-listed
filtering rules (and other actions such as 'rate-limit'). The
applicability of DOTS in such case is as follows:
o The DMS generates a list of flow tuples (e.g., 5-tuples) which the
DMS is blocking/rate-limiting and wants to offload.
o The DMS creates ACEs for each elements of the list, setting
"matches" as the flow tuple and "forwarding" in "actions" as
"drop" (or other actions).
o The DMS aggregates the ACEs under an ACL set, and the DMS sends
the ACL to the orchestrator setting "activation-type" as
"immediate".
Figure 3 shows a JSON example of ACL conveyed by DOTS data channel.
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{
"ietf-dots-data-channel:acls": {
"acl": [
{
"name": "DMS_Offload_Usecase_ACL",
"type": "ipv4-acl-type",
"activation-type": "immediate",
"aces": {
"ace": [
{
"name": "DMS_Offload_Usecase_ACE_00",
"matches": {
"ipv4": {
"destination-ipv4-network": "192.0.2.2/32",
"source-ipv4-network": "203.0.113.2/32",
"protocol":17
},
"udp": {
"source-port": {
"operator": "eq",
"port": 53
}
}
},
"actions": {
"forwarding": "drop"
}
}
]
}
}
]
}
}
Figure 3: JSON Example of ACL conveyed by DOTS data channel
4.3. Case: Mitigation Request via In-band Link
In this case, the DMS sends a mitigation request to the orchestrator
with information of blocked traffic by the DMS via in-band channel.
The link can be congested when it is under volume attack-time, so
DOTS data channel can't be used to convey the drop-listed filtering
rules as blocked traffic information [Interop].
The DOTS signal channel and [I-D.ietf-dots-signal-channel] and the
source-* clauses defined in [I-D.reddy-dots-home-network] are used to
communicate the policies to the orchestrator.
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<<<An example will be included>>>>
5. Security Considerations
Security considerations discussed in [I-D.ietf-dots-data-channel] and
[I-D.ietf-dots-signal-channel] are to be taken into account.
6. IANA Considerations
This document does not require any action from IANA.
7. Acknowledgement
Thanks to Tirumaleswar Reddy, Shunsuke Homma for the comments.
Thanks to Koichi Sakurada for demonstrating proof of concepts of this
use case.
8. References
8.1. Normative References
[I-D.ietf-dots-data-channel]
Boucadair, M. and R. K, "Distributed Denial-of-Service
Open Threat Signaling (DOTS) Data Channel Specification",
draft-ietf-dots-data-channel-27 (work in progress),
February 2019.
[I-D.ietf-dots-requirements]
Mortensen, A., K, R., and R. Moskowitz, "Distributed
Denial of Service (DDoS) Open Threat Signaling
Requirements", draft-ietf-dots-requirements-20 (work in
progress), February 2019.
[I-D.ietf-dots-signal-channel]
K, R., Boucadair, M., Patil, P., Mortensen, A., and N.
Teague, "Distributed Denial-of-Service Open Threat
Signaling (DOTS) Signal Channel Specification", draft-
ietf-dots-signal-channel-30 (work in progress), March
2019.
[I-D.ietf-dots-use-cases]
Dobbins, R., Migault, D., Fouant, S., Moskowitz, R.,
Teague, N., Xia, L., and K. Nishizuka, "Use cases for DDoS
Open Threat Signaling", draft-ietf-dots-use-cases-17 (work
in progress), January 2019.
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8.2. Informative References
[I-D.nishizuka-dots-signal-control-filtering]
Nishizuka, K., Boucadair, M., K, R., and T. Nagata,
"Controlling Filtering Rules Using DOTS Signal Channel",
draft-nishizuka-dots-signal-control-filtering-04 (work in
progress), February 2019.
[I-D.reddy-dots-home-network]
K, R., Harsha, J., Boucadair, M., and J. Shallow, "Denial-
of-Service Open Threat Signaling (DOTS) Signal Channel
Call Home", draft-reddy-dots-home-network-03 (work in
progress), December 2018.
[Interop] Nishizuka, K., Shallow, J., and L. Xia , "DOTS Interop
test report, IETF 103 Hackathon", November 2018,
<https://datatracker.ietf.org/meeting/103/materials/
slides-103-dots-interop-report-from-ietf-103-hackathon-
00>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/info/rfc4271>.
[RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
and D. McPherson, "Dissemination of Flow Specification
Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009,
<https://www.rfc-editor.org/info/rfc5575>.
[RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object
Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049,
October 2013, <https://www.rfc-editor.org/info/rfc7049>.
Authors' Addresses
Yuhei Hayashi (editor)
NTT
3-9-11, Midori-cho
Musashino-shi, Tokyo 180-8585
Japan
Email: yuuhei.hayashi@gmail.com, yuuhei.hayashi.mr@hco.ntt.co.jp
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Kaname Nishizuka (editor)
NTT Communications
GranPark 16F 3-4-1 Shibaura, Minato-ku
Tokyo 108-8118
Japan
Email: kaname@nttv6.jp
Mohamed Boucadair (editor)
Orange
Rennes 35000
France
Email: mohamed.boucadair@orange.com
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