Authentication Mechanisms for ONC RPC
RFC 2695
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RFC - Informational
(September 1999; No errata)
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Author |
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Alex Chiu
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Last updated |
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2013-03-02
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Internet Engineering Task Force (IETF)
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RFC 2695 (Informational)
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Network Working Group A. Chiu
Request for Comments: 2695 Sun Microsystems
Category: Informational September 1999
Authentication Mechanisms for ONC RPC
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (1999). All Rights Reserved.
ABSTRACT
This document describes two authentication mechanisms created by Sun
Microsystems that are commonly used in conjunction with the ONC
Remote Procedure Call (ONC RPC Version 2) protocol.
WARNING
The DH authentication as defined in Section 2 in this document refers
to the authentication mechanism with flavor AUTH_DH currently
implemented in ONC RPC. It uses the underlying Diffie-Hellman
algorithm for key exchange. The DH authentication defined in this
document is flawed due to the selection of a small prime for the BASE
field (Section 2.5). To avoid the flaw a new DH authentication
mechanism could be defined with a larger prime. However, the new DH
authentication would not be interoperable with the existing DH
authentication.
As illustrated in [10], a large number of attacks are possible on ONC
RPC system services that use non-secure authentication mechanisms.
Other secure authentication mechanisms need to be developed for ONC
RPC. RFC 2203 describes the RPCSEC_GSS ONC RPC security flavor, a
secure authentication mechanism that enables RPC protocols to use
Generic Security Service Application Program Interface (RFC 2078) to
provide security services, integrity and privacy, that are
independent of the underlying security mechanisms.
Chiu Informational [Page 1]
RFC 2695 Authentication Mechanisms for ONC RPC September 1999
Table of Contents
1. Introduction ............................................... 2
2. Diffie-Hellman Authentication .............................. 2
2.1 Naming .................................................... 3
2.2 DH Authentication Verifiers ............................... 3
2.3 Nicknames and Clock Synchronization ....................... 5
2.4 DH Authentication Protocol Specification .................. 5
2.4.1 The Full Network Name Credential and Verifier (Client) .. 6
2.4.2 The Nickname Credential and Verifier (Client) ........... 8
2.4.3 The Nickname Verifier (Server) .......................... 9
2.5 Diffie-Hellman Encryption ................................. 9
3. Kerberos-based Authentication ............................. 10
3.1 Naming ................................................... 11
3.2 Kerberos-based Authentication Protocol Specification ..... 11
3.2.1 The Full Network Name Credential and Verifier (Client) . 12
3.2.2 The Nickname Credential and Verifier (Client) .......... 14
3.2.3 The Nickname Verifier (Server) ......................... 15
3.2.4 Kerberos-specific Authentication Status Values ......... 15
4. Security Considerations ................................... 16
5. REFERENCES ................................................ 16
6. AUTHOR'S ADDRESS .......................................... 17
7. FULL COPYRIGHT STATEMENT ...................................18
1. Introduction
The ONC RPC protocol provides the fields necessary for a client to
identify itself to a service, and vice-versa, in each call and reply
message. Security and access control mechanisms can be built on top
of this message authentication. Several different authentication
protocols can be supported.
This document specifies two authentication protocols created by Sun
Microsystems that are commonly used: Diffie-Hellman (DH)
authentication and Kerberos (Version 4) based authentication.
As a prerequisite to reading this document, the reader is expected to
be familiar with [1] and [2]. This document uses terminology and
definitions from [1] and [2].
2. Diffie-Hellman Authentication
System authentication (defined in [1]) suffers from some problems.
It is very UNIX oriented, and can be easily faked (there is no
attempt to provide cryptographically secure authentication).
Chiu Informational [Page 2]
RFC 2695 Authentication Mechanisms for ONC RPC September 1999
DH authentication was created to address these problems. However, it
has been compromised [9] due to the selection of a small length for
the prime in the ONC RPC implementation. While the information
provided here will be useful for implementors to ensure
interoperability with existing applications that use DH
authentication, it is strongly recommended that new applications use
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