Internet DRAFT - draft-boucadair-dots-dhcp
draft-boucadair-dots-dhcp
Network Working Group M. Boucadair
Internet-Draft Orange
Intended status: Standards Track April 12, 2017
Expires: October 14, 2017
DHCP Options for Distributed-Denial-of-Service Open Threat Signaling
(DOTS)
draft-boucadair-dots-dhcp-01
Abstract
It may not be possible for a network to determine the cause for an
attack, but instead just realize that some resources seem to be under
attack. To fill that gap, Distributed-Denial-of-Service Open Threat
Signaling (DOTS) allows a network to inform a server that it is under
a potential attack so that appropriate mitigation actions are
undertaken.
This document specifies DHCP (IPv4 and IPv6) options to configure
hosts with DOTS servers.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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This Internet-Draft will expire on October 14, 2017.
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Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Design Rationale . . . . . . . . . . . . . . . . . . . . . . 4
4. DHCPv6 DOTS Option . . . . . . . . . . . . . . . . . . . . . 4
4.1. Format . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.2. DHCPv6 Client Behavior . . . . . . . . . . . . . . . . . 5
5. DHCPv4 DOTS Option . . . . . . . . . . . . . . . . . . . . . 6
5.1. Format . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.2. DHCPv4 Client Behavior . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7.1. DHCPv6 Option . . . . . . . . . . . . . . . . . . . . . . 7
7.2. DHCPv4 Option . . . . . . . . . . . . . . . . . . . . . . 7
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
9.1. Normative References . . . . . . . . . . . . . . . . . . 7
9.2. Informative References . . . . . . . . . . . . . . . . . 8
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
In many deployments, it may not be possible for a network to
determine the cause for a distributed Denial-of-Service (DoS) attack
[RFC4732], but instead just realize that some resources seem to be
under attack. To fill that gap, the IETF is specifying an
architecture, called DDoS Open Threat Signaling (DOTS)
[I-D.ietf-dots-architecture], in which a DOTS client can inform a
DOTS server that the network is under a potential attack and that
appropriate mitigation actions are required. Indeed, because the
lack of a common method to coordinate a real-time response among
involved actors and network domains inhibits the effectiveness of
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DDoS attack mitigation, DOTS protocol is meant to carry requests for
DDoS attack mitigation, thereby reducing the impact of an attack and
leading to more efficient defensive actions.
[I-D.ietf-dots-use-cases] identifies a set of scenarios for DOTS;
almost all these scenarios involve a CPE.
The basic high-level DOTS architecture is illustrated in Figure 1
([I-D.ietf-dots-architecture]):
+-----------+ +-------------+
| Mitigator | ~~~~~~~~~~ | DOTS Server |
+-----------+ +-------------+
|
|
|
+---------------+ +-------------+
| Attack Target | ~~~~~~ | DOTS Client |
+---------------+ +-------------+
Figure 1: Basic DOTS Architecture
[I-D.ietf-dots-architecture] specifies that the DOTS client may be
provided with a list of DOTS servers; each associated with one or
more IP addresses. These addresses may or may not be of the same
address family. The DOTS client establishes one or more signaling
sessions by connecting to the provided DOTS server addresses.
To that aim, this document defines DHCPv4 [RFC2131] and DHCPv6
[RFC3315] options that can be used to configure hosts, embedding a
DOTS client, with DOTS servers' names. These names will be resolved
into one or a list of IP addresses.
The use of DHCP for DOTS provisioning is justified because many of
the target use cases identified in [I-D.ietf-dots-use-cases] involve
CPEs; these devices widely support DHCP.
Also, the use of DHCP to provision a name that will be resolved into
one or many unicast address(es) of the appropriate DOTS server
instance(s) to contact does not suffer from the complications
encountered if a anycast address is used (see Section 3.2.4.1 of
[I-D.ietf-dots-architecture]). The use of DHCP ensures a
deterministic behavior.
2. Terminology
This document makes use of the following terms:
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o DOTS client: A DOTS-aware software module responsible for
requesting attack response coordination with other DOTS-aware
elements.
o DOTS server: A DOTS-aware software module handling and responding
to messages from DOTS clients. The DOTS server should enable
mitigation on behalf of the DOTS client, if requested, by
communicating the DOTS client's request to the mitigator and
returning selected mitigator feedback to the requesting DOTS
client. A DOTS server may also be a mitigator.
o DDoS: A distributed Denial-of-Service attack, in which traffic
originating from multiple sources are directed at a target on a
network. DDoS attacks are intended to cause a negative impact on
the availability of servers, services, applications, and/or other
functionality of an attack target.
o DHCP refers to both DHCPv4 [RFC2131] and DHCPv6 [RFC3315].
o DHCP client denotes a node that initiates requests to obtain
configuration parameters from one or more DHCP servers.
o DHCP server refers to a node that responds to requests from DHCP
clients.
3. Design Rationale
As reported in Section 1.7.2 of [RFC6125], "few certification
authorities issue server certificates based on IP addresses, but
preliminary evidence indicates that such certificates are a very
small percentage (less than 1%) of issued certificates". In order to
allow for PKIX-based authentication between a DOTS client and server,
this document specifies the DHCP option as a name. One or multiple
IP addresses may be returned as a result of name resolution.
Defining the option to include a list of IP addresses would avoid a
dependency on an underlying name resolution, but that design requires
to also supply a name for PKIX-based authentication purposes.
Because aliasing is to be avoided (Section 7 of [RFC7227]), this
document specifies one single option that conveys a DOTS server's
name.
4. DHCPv6 DOTS Option
4.1. Format
The DHCPv6 DOTS option is used to configure a name of the DOTS
server. The format of this option is shown in Figure 2.
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_V6_DOTS | Option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| dots-server-name (FQDN) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: DHCPv6 DOTS option
The fields of the option shown in Figure 2 are as follows:
o Option-code: OPTION_V6_DOTS (TBA, see Section 7.1)
o Option-length: Length of the dots-server-name field in octets.
o dots-server-name: A fully qualified domain name of the DOTS
server. This field is formatted as specified in Section 8 of
[RFC3315].
An example of the dots-server-name encoding is shown in Figure 3.
This example conveys the FQDN "dots.example.com.".
+------+------+------+------+------+------+------+------+------+
| 0x04 | d | o | t | s | 0x07 | e | x | a |
+------+------+------+------+------+------+------+------+------+
| m | p | l | e | 0x03 | c | o | m | 0x00 |
+------+------+------+------+------+------+------+------+------+
Figure 3: An example
4.2. DHCPv6 Client Behavior
Clients MAY request option OPTION_V6_DOTS, as defined in [RFC3315],
Sections 17.1.1, 18.1.1, 18.1.3, 18.1.4, 18.1.5, and 22.7. As a
convenience to the reader, we mention here that the client includes
requested option codes in the Option Request Option.
If the DHCP client receives more than one OPTION_V6_DOTS option, it
MUST use only the first instance of that option.
If the OPTION_V6_DOTS option contains more than one name, as
distinguished by the presence of multiple root labels, the DHCP
client MUST use only the first name. Once the name is validated
(Section 8 of [RFC3315]), the name is passed to a name resolution
library.
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5. DHCPv4 DOTS Option
5.1. Format
The DHCPv4 DOTS option is used to configure a name of the DOTS
server. The format of this option is illustrated in Figure 4.
Code Length DOTS server name
+-----+-----+-----+-----+-----+-----+-----+--
| TBA | n | s1 | s2 | s3 | s4 | s5 | ...
+-----+-----+-----+-----+-----+-----+-----+--
The values s1, s2, s3, etc. represent the domain name labels in the
domain name encoding.
Figure 4: DHCPv4 DOTS option
The fields of the option shown in Figure 4 are as follows:
o Code: OPTION_V4_DOTS (TBA, see Section 7.2);
o Length: Includes the length of the "DOTS server name" field in
octets; the maximum length is 255 octets.
o DOTS server name: The domain name of the DOTS server. This field
is formatted as specified in Section 8 of [RFC3315].
5.2. DHCPv4 Client Behavior
To discover a DOTS server, the DHCPv4 client MUST include
OPTION_V4_DOTS in a Parameter Request List Option [RFC2132].
If the DHCP client receives more than one OPTION_V4_DOTS option, it
MUST use only the first instance of that option.
If the OPTION_V4_DOTS option contains more than one name, as
distinguished by the presence of multiple root labels, the DHCP
client MUST use only the first FQDN. Once the name is validated
(Section 8 of [RFC3315]), the name is passed to a name resolution
library.
6. Security Considerations
The security considerations in [RFC2131] and [RFC3315] are to be
considered.
DOTS-related security considerations are discussed in Section 4 of
[I-D.ietf-dots-architecture].
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7. IANA Considerations
7.1. DHCPv6 Option
IANA is requested to assign the following new DHCPv6 Option Code in
the registry maintained in http://www.iana.org/assignments/
dhcpv6-parameters:
Option Name Value
-------------- -----
OPTION_V6_DOTS TBA
7.2. DHCPv4 Option
IANA is requested to assign the following new DHCPv4 Option Code in
the registry maintained in http://www.iana.org/assignments/bootp-
dhcp-parameters/:
Option Name Value Data length Meaning
-------------- ----- ------------------------- ----------------------
OPTION_V4_DOTS TBA Variable; the maximum Includes the name of
length is 255 octets. the DOTS server.
8. Acknowledgements
Many thanks to Tiru Reddy for his comments.
9. References
9.1. Normative References
[I-D.ietf-dots-architecture]
Mortensen, A., Andreasen, F., Reddy, T.,
christopher_gray3@cable.comcast.com, c., Compton, R., and
N. Teague, "Distributed-Denial-of-Service Open Threat
Signaling (DOTS) Architecture", draft-ietf-dots-
architecture-01 (work in progress), October 2016.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC2131] Droms, R., "Dynamic Host Configuration Protocol",
RFC 2131, DOI 10.17487/RFC2131, March 1997,
<http://www.rfc-editor.org/info/rfc2131>.
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[RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
Extensions", RFC 2132, DOI 10.17487/RFC2132, March 1997,
<http://www.rfc-editor.org/info/rfc2132>.
[RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins,
C., and M. Carney, "Dynamic Host Configuration Protocol
for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July
2003, <http://www.rfc-editor.org/info/rfc3315>.
9.2. Informative References
[I-D.ietf-dots-use-cases]
Dobbins, R., Fouant, S., Migault, D., Moskowitz, R.,
Teague, N., Xia, L., and K. Nishizuka, "Use cases for DDoS
Open Threat Signaling", draft-ietf-dots-use-cases-04 (work
in progress), March 2017.
[RFC4732] Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet
Denial-of-Service Considerations", RFC 4732,
DOI 10.17487/RFC4732, December 2006,
<http://www.rfc-editor.org/info/rfc4732>.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
Verification of Domain-Based Application Service Identity
within Internet Public Key Infrastructure Using X.509
(PKIX) Certificates in the Context of Transport Layer
Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March
2011, <http://www.rfc-editor.org/info/rfc6125>.
[RFC7227] Hankins, D., Mrugalski, T., Siodelski, M., Jiang, S., and
S. Krishnan, "Guidelines for Creating New DHCPv6 Options",
BCP 187, RFC 7227, DOI 10.17487/RFC7227, May 2014,
<http://www.rfc-editor.org/info/rfc7227>.
Author's Address
Mohamed Boucadair
Orange
Rennes 35000
France
Email: mohamed.boucadair@orange.com
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