INCH Working Group K. Moriarty
Internet-Draft RSA
Intended status: Informational B. Trammell
Expires: September 27, 2010 Hitachi Europe
March 26, 2010
Transport of Real-time Inter-network Defense (RID) Messages
draft-moriarty-post-inch-rid-transport-02.txt
Abstract
Documents intended to be shared among multiple constituencies must
share a common format and transport mechanism. The Incident Object
Description Exchange Format (IODEF) defines a common XML format for
document exchange, and Realtime Internetwork Defense (RID) defines
extensions to IODEF intended for the cooperative handling of security
incidents within consortia of network operators and enterprises.
This document outlines the transport of IODEF and RID messages over
HTTP/TLS.
Status of this Memo
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Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Transmission of RID Messages over HTTP/TLS . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7
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1. Introduction
The Incident Object Description Exchange Format (IODEF) [RFC5070]
describes an XML document format for the purpose of exchanging data
between Computer Security Incident Response Teams (CSIRTs) or those
responsible for security incident handling for network providers
(NPs). The defined document format provides an easy way for CSIRTs
to exchange data in a way which can be easily parsed.
IODEF defines a message format, not a transport protocol, as the
sharing of messages is assumed to be out of scope in order to allow
CSIRTs to exchange and store messages in a way most suited to their
established incident handling processes. However, extensions such as
Real-time Inter-network Defense (RID) [I-D.moriarty-post-inch-rid] do
require a specification of a transport protocol to ensure
interoperability among members in a RID consortium. This document
specifies the transport of RID messages within HTTP [RFC2616] Request
and Response messages transported over TLS [RFC5246] (herein, HTTP/
TLS). Note that any IODEF message may also be transported using this
mechanism, by sending it as a RID Report message.
2. Terminology
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 [RFC2119].
3. Transmission of RID Messages over HTTP/TLS
This section specifies the details of the transport of RID messages
over HTTP/TLS. In this arrangement, each RID server is both an HTTP/
TLS server and an HTTP/TLS Client. When a RID message must be sent,
the sending RID system connects to the receiving RID system and sends
the message, optionally receiving a message in reply. All RID
systems MUST be prepared to accept HTTP/TLS connections from any RID
peer with which it communicates, in order to support callback for
delayed replies (see below).
BCP 56 [RFC3205] contains a number of important considerations when
using HTTP for application protocols. These include the size of the
payload for the application, whether the application will use a web
browser, whether the protocol should be defined on a port other than
80, and if the security provided through HTTP/TLS suits the needs of
the new application.
It is acknowledged within the scope of these concerns that HTTP/TLS
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is not ideally suited for RID transport, as the former is a client-
server protocol and the latter a message-exchange protocol; however,
the ease of implementation of RID systems over HTTP/TLS outweighs
these concerns. Consistent with BCP 56, RID systems will listen for
TCP connections on port [IANA NOTE: assigned port goes here]. Every
RID system participating in a consortium MUST listen for HTTP/TLS
connections on the assigned port.
All RID messages sent in HTTP Requests MUST be sent using the POST
with a Request-URI of /; additional Request-URI paths are reserved
for future use by RID.
The following table lists the allowable RID message types in an HTTP
Response for a given RID message type in the Request. A RID system
MUST be prepared to handle an HTTP Response of the given type(s) when
sending the corresponding HTTP Request. A RID system MUST NOT send
an HTTP Response containing any RID message other than the one
corresponding to the one sent in the HTTP Request.
As the queries and replies in a RID message exchange may be
significantly separated in time, the receiving RID system MAY return
202 Accepted, terminate the connection, and connect to the requesting
RID system and sending the RID reply in an HTTP Request at a later
time. This mechanism is referred to in this document as "RID
callback". When performing RID callback, a responding system MUST
connect to the network- and transport-layer addresses from which the
original request was sent; there is no mechanism in RID for
redirected callback.
While a RID system SHOULD return the reply in an HTTP Response if it
is available immediately or within a generally accepted HTTP client
time out (about thirty seconds), this is not mandatory, and as such
RID systems MUST be prepared for a query to be met with a 202
Accepted, an empty Response body, a connection termination and a
callback.
RID systems accepting a callback message in an HTTP Request MUST
return 202 Accepted.
The following table lists the allowable request/response pairs for
RID.
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+----------------------+----------+--------+----------------------+
| Request RID type | Callback | Result | Response RID type |
+----------------------+----------+--------+----------------------+
| TraceRequest | | 200 | RequestAuthorization |
| TraceRequest | | 200 | Result |
| TraceRequest | | 202 | [empty] |
| RequestAuthorization | X | 202 | [empty] |
| Result | X | 202 | [empty] |
| Investigation | | 200 | Result |
| Investigation | | 202 | [empty] |
| Report | X | 202 | [empty] |
| IncidentQuery | | 200 | Report |
| IncidentQuery | | 202 | [empty] |
+----------------------+----------+--------+----------------------+
For security purposes, RID systems SHOULD NOT return 3xx Redirect
response codes, and MUST NOT follow any 3xx Redirect. When a RID
System's address changes, contact point information within the
consortium must be updated out of band.
If a RID system receives an improper RID message in an HTTP Request,
it MUST return an appropriate 4xx Client Error result code to the
requesting RID system. If a RID system cannot process a RID message
received in an HTTP Request due to an error on its own side, it MUST
return an appropriate 5xx Server Error result code to the requesting
RID system.
Note that HTTP provides no mechanism for signaling to a server than a
response body is improper. If an RID system receives and improper
RID message in an HTTP Response, or cannot process a RID message
received in an HTTP Response due to an error on its own side, it MUST
log the error and present it to the RID system administrator for
handling; the error logging format is an implementation detail and is
considered out of scope for this specification.
RID systems MUST support and SHOULD use HTTP/1.1 persistent
connections as described in [RFC2616] to minimize TCP connection
setup overhead. RID systems MUST support chunked transfer encoding
on the HTTP server side to allow the implementation of clients that
do not need to precalculate message sizes before constructing HTTP
headers.
RID systems MUST use TLS for confidentiality, identification, and
strong mutual authentication as in [RFC2818]; see Section 4 below for
details.
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4. Security Considerations
All security considerations of related documents MUST be considered,
especially the Incident Object Description Exchange Format (IODEF)
[RFC5070] and Real-time Inter-network Defense (RID)
[I-D.moriarty-post-inch-rid]. The transport described herein is
built on the foundation of these documents; the security
considerations contained therein are incorporated by reference.
For transport confidentiality, identification, and authentication,
TLS with mutual authentication MUST be used to secure the HTTP
connection as in [RFC2818]. Each RID consortium SHOULD use a trusted
public key infrastructure (PKI) to manage identities dor RID systems
participating in TLS connections. At minimum, each RID system MUST
trust a set of X.509 Issuer identities ("Certificate Authorities") to
authenticate RID system peers with which it is willing to exchange
information, and/or a specific white list of X.509 Subject identities
of RID system peers directly.
RID systems SHOULD additionally verify the fully qualified domain
name (FQDN) of a connected RID system peer against the presented
Subject identity. The fully qualified domain name used to identify a
RID system may be stored either in a subjectAltName extension of type
dNSName, or in the most specific Common Name field of the Subject
identity of the RID system's X.509 certificate. Internationalized
FQDNs MUST be encoded using Punycode [RFC3492]. If both a Common
Name and subjectAltName FQDN are present, the subjectAltName is to be
given preference.
5. IANA Considerations
Consistent with BCP 56 [RFC3205], since RID over HTTP/TLS is a
substantially new service, and should be controlled at the consortium
member network's border differently than HTTP/TLS, it requires a new
port number. IANA has assigned port [IANA NOTE: assign port number
here] to RID over HTTP/TLS.
6. References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
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[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
[RFC3205] Moore, K., "On the use of HTTP as a Substrate", BCP 56,
RFC 3205, February 2002.
[RFC3492] Costello, A., "Punycode: A Bootstring encoding of Unicode
for Internationalized Domain Names in Applications
(IDNA)", RFC 3492, March 2003.
[RFC5070] Danyliw, R., Meijer, J., and Y. Demchenko, "The Incident
Object Description Exchange Format", RFC 5070,
December 2007.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008.
[I-D.moriarty-post-inch-rid]
Moriarty, K., "Real-time Inter-network Defense",
draft-moriarty-post-inch-rid-10 (work in progress),
February 2010.
Authors' Addresses
Kathleen M. Moriarty
RSA, The Security Division of EMC
174 Middlesex Turnpike
Bedford 01730
United States
Email: Moriarty_Kathleen@EMC.com
Brian H. Trammell
Hitachi Europe
c/o ETH Zurich
Gloriastrasse 35
8092 Zurich
Switzerland
Phone: +41 44 632 70 13
Email: brian.trammell@hitachi-eu.com
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