Distributed Denial-of-Service Open
Threat Signaling (DOTS) Data ChannelMcAfee, Inc.Embassy Golf Link Business ParkBangaloreKarnataka560071Indiakondtir@gmail.comOrangeRennes35000Francemohamed.boucadair@orange.comNTT CommunicationsGranPark 16F 3-4-1 Shibaura, Minato-kuTokyo108-8118Japankaname@nttv6.jpHuawei101 Software Avenue, Yuhuatai DistrictNanjing, Jiangsu210012Chinafrank.xialiang@huawei.comCisco Systems, Inc.praspati@cisco.comArbor Networks, Inc.2727 S. State StAnn Arbor, MI48104United Statesamortensen@arbor.netVerisign, Inc.United Statesnteague@verisign.comDOTSThe document specifies a Distributed Denial-of-Service Open Threat
Signaling (DOTS) data channel used for bulk exchange of data not easily
or appropriately communicated through the DOTS signal channel under
attack conditions. This is a companion document to the DOTS signal
channel specification.A distributed denial-of-service (DDoS) attack is an attempt to make
machines or network resources unavailable to their intended users. In
most cases, sufficient scale can be achieved by compromising enough
end-hosts and using those infected hosts to perpetrate and amplify the
attack. The victim in this attack can be an application server, a
client, a router, a firewall, or an entire network.DDoS Open Threat Signaling (DOTS) defines two channels: signal
and data channels (). The DOTS signal
channel used to convey that a network is under a DDOS attack to an
upstream DOTS server so that appropriate mitigation actions are
undertaken on the suspect traffic is further elaborated in . The DOTS data channel is
used for infrequent bulk data exchange between DOTS agents in the aim to
significantly augment attack response coordination. | |
| DOTS Client | | DOTS Server |
| | <======= Data Channel ======> | |
+---------------+ +---------------+]]>Section 2 of
identifies that the DOTS data channel is used to perform the tasks
listed below:Filter management, which enables a DOTS client to request the
installation or removal of traffic filters, dropping or
rate-limiting unwanted traffic and permitting white-listed traffic.
Sample use cases for populating black- or white-list filtering rules
are detailed hereafter: If a network resource (DOTS client) detects a potential DDoS
attack from a set of IP addresses, the DOTS client informs its
servicing router (DOTS gateway) of all suspect IP addresses that
need to be blocked or black-listed for further investigation.
The DOTS client could also specify a list of protocols and ports
in the black-list rule. That DOTS gateway in-turn propagates the
black-listed IP addresses to the DOTS server which will
undertake appropriate action so that traffic from these IP
addresses to the target network (specified by the DOTS client)
is blocked.A network has partner sites from which only legitimate
traffic arrives and the network wants to ensure that the traffic
from these sites is not penalized during DDOS attacks. The DOTS
client uses the DOTS data channel to convey the white-listed IP
addresses or prefixes of the partner sites to its DOTS server.
The DOTS server uses this information to white-list flows from
such IP addresses or prefixes reaching the network.Creating identifiers, such as names or aliases, for resources for
which mitigation may be requested:The DOTS client may submit to the DOTS server a collection of
prefixes which it would like to refer to by alias when
requesting mitigation. The server can respond to this request
with either with a success or failure response (see requirement
OP-006 in and
Section 2 in ).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 .The reader should be familiar with the terms defined in .The terminology for describing YANG data modules is defined in . The meaning of the symbols in tree diagrams is
defined in .For simplicity, all of the examples in this document use "/restconf"
as the discovered RESTCONF API root path. Many protocol header lines and
message-body text within examples throughout the document are split into
multiple lines for display purposes only. When a line ends with
backslash ('\') as the last character, the line is wrapped for display
purposes. It is to be considered to be joined to the next line by
deleting the backslash, the following line break, and the leading
whitespace of the next line.The DOTS data channel is intended to be used for bulk data exchanges
between DOTS agents. Unlike the signal channel , which must operate
nominally even when confronted with signal degradation due to packets
loss, the data channel is not expected to be constructed to deal with
DDoS attack conditions.As the primary function of the data channel is data exchange, a
reliable transport is required in order for DOTS agents to detect data
delivery success or failure. RESTCONF
over TLS over TCP is used for DOTS data
channel (). RESTCONF uses HTTP methods
to provide CRUD (create, read, update, delete) operations on a
conceptual datastore containing YANG data, which is compatible with a
server implementing NETCONF datastores.The HTTP POST, PUT, PATCH, and DELETE methods are used to edit data
resources represented by DOTS data channel YANG data models. These basic
edit operations allow the DOTS data channel running configuration to be
altered by a DOTS client.DOTS data channel configuration data and state data can be retrieved
with the GET method. HTTP status codes are used to report success or
failure for RESTCONF operations.The DOTS client will perform the root resource discovery procedure
discussed in Section 3.1 of to determine
the root of the RESTCONF API. After discovering the RESTCONF API root,
the DOTS client uses this value as the initial part of the path in the
request URI, in any subsequent request to the DOTS server. The DOTS
server may support retrieval of the YANG modules it supports (Section
3.7 in ), for example, a DOTS client may
use RESTCONF to retrieve the company proprietary YANG modules supported
by the DOTS server.Note: This document uses RESTCONF, a protocol based on HTTP , for configuring data defined in YANG
version 1 or YANG version 1.1 , using the datastore concepts defined in
the Network Configuration Protocol (NETCONF) . RESTCONF combines the simplicity of the
HTTP protocol with the predictability and automation potential of a
schema-driven API. RESTCONF offers a simple subset of NETCONF
functionality and provides a simplified interface using REST-like
API which addresses the needs of the DOTS data channel and hence an
optimal choice.JavaScript Object Notation (JSON)
payload is used to propagate data channel specific payload messages that
convey request parameters and response information such as errors. This
specification uses the encoding rules defined in for representing DOTS data channel
configuration data defined using YANG () as
JSON text.A DOTS client registers itself to its DOTS server(s) in order to set
up DOTS data channel related configuration data and receive state data
(i.e., non-configuration data) from the DOTS server(s).A single DOTS data channel between DOTS agents can be used to
exchange multiple requests and multiple responses. To reduce DOTS client
and DOTS server workload, DOTS client SHOULD re-use the same TLS
session. While the communication to the DOTS server is quiescent, the
DOTS client MAY probe the server to ensure it has maintained
cryptographic state. Such probes can also keep alive firewall and/or NAT
bindings. A TLS heartbeat verifies the
DOTS server still has TLS state by returning a TLS message.This document defines a YANG module for creating identifiers,
such as names or aliases, for resources for which mitigation may be
requested. Such identifiers may be used in subsequent DOTS signal
channel exchanges to refer more efficiently to the resources under
attack.This document defines the YANG module
"ietf-dots-data-channel-identifier", which has the following tree
structure:This structure is aligned with Section 5.2.1 of . file "ietf-dots-data-channel-identifier@2017-10-12.yang"
module ietf-dots-data-channel-identifier {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-dots-data-channel-identifier";
prefix "alias";
import ietf-inet-types {
prefix "inet";
}
organization "IETF DOTS Working Group";
contact
"Konda, Tirumaleswar Reddy
Mohamed Boucadair
Kaname Nishizuka
Liang Xia
Prashanth Patil
Andrew Mortensen
Nik Teague ";
description
"This module contains YANG definition for configuring
identifiers for resources using DOTS data channel.
Copyright (c) 2017 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices.";
revision 2017-10-12 {
description "Fix nits and align the module with the signal
channel.";
reference
"-05";
}
revision 2017-08-03 {
reference
"https://tools.ietf.org/html/draft-ietf-dots-data-channel";
}
container identifier {
description "Top level container for identifiers";
leaf-list client-identifier {
type binary;
description "A client identifier conveyed by a DOTS gateway
to a remote DOTS server.";
reference
"I-D.itef-dots-signal-channel";
}
list alias {
key alias-name;
description "List of identifiers";
leaf alias-name {
type string;
description "alias name";
}
leaf-list target-ip {
type inet:ip-address;
description "IPv4 or IPv6 address identifying the target.";
}
leaf-list target-prefix {
type inet:ip-prefix;
description "IPv4 or IPv6 prefix identifying the target.";
}
list target-port-range {
key "lower-port upper-port";
description
"Port range. When only lower-port is present,
it represents a single port.";
leaf lower-port {
type inet:port-number;
mandatory true;
description "Lower port number.";
}
leaf upper-port {
type inet:port-number;
must ". >= ../lower-port" {
error-message
"The upper-port must be greater than or
equal to lower-port";
}
description "Upper port number.";
}
}
leaf-list target-protocol {
type uint8;
description "Identifies the target protocol number.";
reference
"https://www.iana.org/assignments/protocol-numbers/
protocol-numbers.xhtml";
}
leaf-list fqdn {
type inet:domain-name;
description "FQDN";
}
leaf-list uri {
type inet:uri;
description "URI";
}
}
}
}
]]>This document augments the "ietf-access-control-list" Access
Control List (ACL) YANG module for managing filtering
rules. ACL is explained in Section 1 of .Examples of ACL management include, but not limited to,:Black-list management, which enables a DOTS client to inform
the DOTS server about sources from which traffic should be
suppressed.White-list management, which enables a DOTS client to inform
the DOTS server about sources from which traffic should always
be accepted.Filter management, which enables a DOTS client to request the
installation or removal of traffic filters, dropping or
rate-limiting unwanted traffic and permitting white-listed
traffic.This document defines the YANG module
"ietf-dots-access-control-list" to augment the
"ietf-access-control-list" module to support filters based on the
client identifier (client-identifier), to support rate-limit action
(rate-limit), and to handle fragmented packets (fragments).Filtering fragments adds an additional layer of protection
against a DoS attack that uses only noninitial fragments. When there
is only Layer 3 information in the ACL entry and the fragments
keyword is present, for noninitial fragments matching the ACL entry,
the deny or permit action associated with the ACL entry will be
enforced and for initial or non-fragment matching the ACL entry, the
next ACL entry will be processed. When there is both Layer 3 and
Layer 4 information in the ACL entry and the fragments keyword is
present, the ACL action is conservative for both permit and deny
actions. The actions are conservative to not accidentally deny a
fragmented portion of a flow because the fragments do not contain
sufficient information to match all of the filter attributes. In the
deny action case, instead of denying a non-initial fragment, the
next ACL entry is processed. In the permit case, it is assumed that
the Layer 4 information in the non-initial fragment, if available,
matches the Layer 4 information in the ACL entry.The "ietf-dots-access-control-list" module has the following
structure: file "ietf-dots-access-control-list@2017-10-12.yang"
module ietf-dots-access-control-list {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-dots-access-control-list";
prefix "dots-acl";
import ietf-access-control-list {
prefix "ietf-acl";
}
organization "IETF DOTS Working Group";
contact
"Konda, Tirumaleswar Reddy
Mohamed Boucadair
Kaname Nishizuka
Liang Xia
Prashanth Patil
Andrew Mortensen
Nik Teague ";
description
"This module contains YANG definition for configuring
filtering rules using DOTS data channel.
Copyright (c) 2017 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices.";
revision 2017-10-12 {
description "Fix nits and align the module with the signal
channel.";
reference
"-05";
}
revision 2017-06-12 {
reference
"https://tools.ietf.org/html/draft-ietf-dots-data-channel";
}
augment "/ietf-acl:access-lists" {
description "client-identifier parameter.";
leaf-list client-identifier {
type binary;
description "A client identifier conveyed by a DOTS gateway
to a remote DOTS server.";
}
}
augment "/ietf-acl:access-lists/ietf-acl:acl/ietf-acl:aces/"
+ "ietf-acl:ace/ietf-acl:actions" {
description "rate-limit action";
leaf rate-limit {
type decimal64 {
fraction-digits 2;
}
description "rate-limit action.";
}
}
augment "/ietf-acl:access-lists/ietf-acl:acl/ietf-acl:aces/ietf-acl:ace" {
description "Handle non-initial and initial fragments.";
leaf fragments {
type empty;
description "Handle fragments.";
}
}
}
]]>A POST request is used to create identifiers, such as names or
aliases, for resources for which a mitigation may be requested. Such
identifiers may then be used in subsequent DOTS signal channel
exchanges to refer more efficiently to the resources under attack
().The header parameters are described below:This attribute has the same
meaning, syntax and processing rules as the 'client-identifier'
attribute defined in . This is an
optional attribute.Name of the alias. This is a mandatory
attribute.IP addresses are separated by commas.
This is an optional attribute.Prefixes are separated by commas.
This is an optional attribute.The port range, lower-port for
lower port number and upper-port for upper port number. For TCP,
UDP, SCTP, or DCCP: the range of ports (e.g., 80 to 8080). This
is an optional attribute.Values are taken from the IANA
protocol registry . The
value 0 has a special meaning for 'all protocols'. This is an
optional attribute.Fully Qualified Domain Name, is the full
name of a system, rather than just its hostname. For example,
"venera" is a hostname, and "venera.isi.edu" is an FQDN. This is
an optional attribute.Uniform Resource Identifier (URI). This is
an optional attribute.In the POST request at least one of the attributes 'target-ip' or
'target-prefix' or 'fqdn' or 'uri' MUST be present. DOTS agents can
safely ignore Vendor-Specific parameters they don't understand. shows a POST request to create
alias called "https1" for HTTP(S) servers with IP addresses
2001:db8:6401::1 and 2001:db8:6401::2 listening on port 443.The DOTS server indicates the result of processing the POST
request using HTTP response codes. HTTP 2xx codes are success, HTTP
4xx codes are some sort of invalid requests and 5xx codes are
returned if the DOTS server has erred or it is incapable of
accepting the alias. Response code 201 (Created) will be returned in
the response if the DOTS server has accepted the alias. If the
request is missing one or more mandatory attributes then 400 (Bad
Request) will be returned in the response or if the request contains
invalid or unknown parameters then 400 (Invalid query) will be
returned in the response. The HTTP response will include the JSON
body received in the request.The DOTS client can use the PUT request (Section 4.5 in ) to create or modify the aliases in the
DOTS server.A DELETE request is used to delete identifiers maintained by a
DOTS server ().In RESTCONF, URI-encoded path expressions are used. A RESTCONF
data resource identifier is encoded from left to right, starting
with the top-level data node, according to the 'api-path' rule
defined in Section 3.5.3.1 of . The
data node in the above path expression is a YANG list node and MUST
be encoded according to the rules defined in Section 3.5.1 of .If the DOTS server does not find the alias name conveyed in the
DELETE request in its configuration data, then it responds with a
404 (Not Found) error response code. The DOTS server successfully
acknowledges a DOTS client's request to remove the identifier using
204 (No Content) in the response.A GET request is used to retrieve the set of installed
identifiers from a DOTS server (Section 3.3.1 in ). shows how
to retrieve all the identifiers that were instantiated by the DOTS
client. The content parameter and its permitted values are defined
in Section 4.8.1 of . shows response for all identifiers
on the DOTS server.If the DOTS server does not find the alias name conveyed in the
GET request in its configuration data, then it responds with a 404
(Not Found) error response code.The DOTS server either receives the filtering rules directly from
the DOTS client or via a DOTS gateway.If the DOTS client signals the filtering rules via a DOTS gateway,
then the DOTS gateway validates if the DOTS client is authorized to
signal the filtering rules and if the client is authorized propagates
the rules to the DOTS server. Likewise, the DOTS server validates if
the DOTS gateway is authorized to signal the filtering rules. To
create or purge filters, the DOTS client sends HTTP requests to its
DOTS gateway. The DOTS gateway validates the rules in the requests and
proxies the requests containing the filtering rules to a DOTS server.
When the DOTS gateway receives the associated HTTP response from the
DOTS server, it propagates the response back to the DOTS client.The following APIs define means for a DOTS client to configure
filtering rules on a DOTS server.A POST request is used to push filtering rules to a DOTS server.
shows a POST request example to block
traffic from 192.0.2.0/24, destined to 198.51.100.0/24. The ACL JSON
configuration for the filtering rule is generated using the ACL YANG
data model defined in and the ACL configuration
XML for the filtering rule is specified in Section 4.3 of .The header parameters defined in are discussed below:The name of access-list. This is a
mandatory attribute.Indicates the primary intended type of
match criteria (e.g. IPv4, IPv6). This is a mandatory
attribute.Internet Protocol numbers. This is an
optional attribute.The source IPv4 prefix. This
is an optional attribute.The destination IPv4
prefix. This is an optional attribute."deny" or "permit" or "rate-limit".
"permit" action is used to white-list traffic. "deny" action is
used to black-list traffic. "rate-limit" action is used to
rate-limit traffic, the allowed traffic rate is represented in
bytes per second indicated in IEEE floating point format . If actions attribute is not
specified in the request then the default action is "deny". This
is an optional attribute.The DOTS server indicates the result of processing the POST
request using HTTP response codes. HTTP 2xx codes are success, HTTP
4xx codes are some sort of invalid requests and 5xx codes are
returned if the DOTS server has erred or it is incapable of
configuring the filtering rules. Response code 201 (Created) will be
returned in the response if the DOTS server has accepted the
filtering rules. If the request is missing one or more mandatory
attributes then 400 (Bad Request) will be returned in the response
or if the request contains invalid or unknown parameters then 400
(Invalid query) will be returned in the response.The DOTS client can use the PUT request to create or modify the
filtering rules in the DOTS server.A DELETE request is used to delete filtering rules from a DOTS
server ().If the DOTS server does not find the access list name and access
list type conveyed in the DELETE request in its configuration data,
then it responds with a 404 (Not Found) error response code. The
DOTS server successfully acknowledges a DOTS client's request to
withdraw the filtering rules using 204 (No Content) response code,
and removes the filtering rules as soon as possible.The DOTS client periodically queries the DOTS server to check the
counters for installed filtering rules. A GET request is used to
retrieve filtering rules from a DOTS server. shows how to retrieve all the filtering
rules programmed by the DOTS client and the number of matches for
the installed filtering rules.If the DOTS server does not find the access list name and access
list type conveyed in the GET request in its configuration data,
then it responds with a 404 (Not Found) error response code.This specification registers new parameters for the DOTS data channel
and establishes registries for mappings to JSON attributes.A new registry will be requested from IANA, entitled "DOTS data
channel JSON attribute Mappings Registry". The registry is to be
created as Expert Review Required. JSON attribute name. Brief description of the
attribute. For Standards Track
RFCs, list the "IESG". For others, give the name of the
responsible party. Other details (e.g., postal address, email
address, home page URI) may also be included. Reference to
the document or documents that specify the parameter, preferably
including URIs that can be used to retrieve copies of the
documents. An indication of the relevant sections may also be
included but is not required.JSON Attribute: "client-identifier"Description: Client identifier.Change Controller: IESGSpecification Document(s): this documentJSON Attribute: "alias-name"Description: Name of alias.Change Controller: IESGSpecification Document(s): this documentJSON Attribute: "traffic-protocol"Description: Internet protocol numbers.Change Controller: IESGSpecification Document(s): this documentJSON Attribute: "port-range"Description: The port range, lower-port for lower port number
and upper-port for upper port number. For TCP, UDP, SCTP, or DCCP:
the range of ports (e.g., 80 to 8080).Change Controller: IESGSpecification Document(s): this documentJSON Attribute: "lower-port"Description: Lower port number for port range.Change Controller: IESGSpecification Document(s): this documentJSON Attribute: "upper-port"Description: Upper port number for port range.Change Controller: IESGSpecification Document(s): this documentJSON Attribute: "ip"Description: IP address.Change Controller: IESGSpecification Document(s): this documentJSON Attribute: "prefix"Description: IP prefixChange Controller: IESGSpecification Document(s): this documentJSON Attribute: "fqdn"Description: Fully Qualified Domain Name, is the full name of a
system, rather than just its hostname. For example, "venera" is a
hostname, and "venera.isi.edu" is an FQDN.Change Controller: IESGSpecification Document(s): this documentJSON Attribute: "uri"Description: Uniform Resource Identifier (URI).Change Controller: IESGSpecification Document(s): this documentThe following individuals have contributed to this document:Dan WingEmail: dwing-ietf@fuggles.comAuthenticated encryption MUST be used for data confidentiality and
message integrity. TLS based on client certificate MUST be used for
mutual authentication. The interaction between the DOTS agents requires
Transport Layer Security (TLS) with a cipher suite offering
confidentiality protection and the guidance given in MUST be followed to avoid attacks on TLS.An attacker may be able to inject RST packets, bogus application
segments, etc., regardless of whether TLS authentication is used.
Because the application data is TLS protected, this will not result in
the application receiving bogus data, but it will constitute a DoS on
the connection. This attack can be countered by using TCP-AO . If TCP-AO is used, then any bogus packets
injected by an attacker will be rejected by the TCP-AO integrity check
and therefore will never reach the TLS layer.In order to prevent leaking internal information outside a
client-domain, DOTS gateways located in the client-domain SHOULD NOT
reveal the identity of internal DOTS clients (client-identifier) unless
explicitly configured to do so.Special care should be taken in order to ensure that the activation
of the proposed mechanism won't have an impact on the stability of the
network (including connectivity and services delivered over that
network).Involved functional elements in the cooperation system must establish
exchange instructions and notification over a secure and authenticated
channel. Adequate filters can be enforced to avoid that nodes outside a
trusted domain can inject request such as deleting filtering rules.
Nevertheless, attacks can be initiated from within the trusted domain if
an entity has been corrupted. Adequate means to monitor trusted nodes
should also be enabled.Thanks to Christian Jacquenet, Roland Dobbins, Roman Danyliw, Ehud
Doron, Russ White, Jon Shallow, and Gilbert Clark for the discussion and
comments.Standard for Binary Floating-Point ArithmeticInstitute of Electrical and Electronics
EngineersIANA, "Protocol Numbers"