Network Working Group K. Narayan
Internet-Draft Cisco Systems, Inc.
Intended status: Standards Track D. Nelson
Expires: August 2, 2010 Elbrys Networks, Inc.
R. Presuhn, Ed.
None
January 29, 2010
Extensions to the View-based Access Control Model for use with RADIUS
draft-ietf-isms-radius-vacm-03.txt
Abstract
This memo defines a portion of the Management Information Base (MIB)
for use with network management protocols. In particular, it
describes a backward-compatible extension to the View-based Access
Control Model (VACM) for version 3 of the Simple Network Management
Protocol (SNMPv3) for use with the Remote Authentication Dial-In User
Service (RADIUS) and other Authentication, Authorization, and
Accounting (AAA) services to provide authorization of MIB database
access, and defines objects for managing this extension. This
extension is intended to be used in conjunction with secure SNMP
Transport Models that facilitate RADIUS authentication, such as the
Secure Shell Transport Model.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on August 2, 2010.
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Copyright Notice
Copyright (c) 2010 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
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. The Internet-Standard Management Framework . . . . . . . . . . 4
3. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1. System Block Diagram . . . . . . . . . . . . . . . . . . . 4
4.2. Using RADIUS with SNMP . . . . . . . . . . . . . . . . . . 5
5. Structure of the MIB Module . . . . . . . . . . . . . . . . . 6
5.1. Textual Conventions . . . . . . . . . . . . . . . . . . . 6
5.2. The extVacmCounters Subtree . . . . . . . . . . . . . . . 6
5.3. The Notifications Subtree . . . . . . . . . . . . . . . . 6
5.4. The Table Structures . . . . . . . . . . . . . . . . . . . 6
6. Relationship to Other MIB Modules . . . . . . . . . . . . . . 7
6.1. Relationship to the VACM MIB . . . . . . . . . . . . . . . 7
6.1.1. Extended VACM for RADIUS Authorization . . . . . . . . 7
6.1.2. VACM Extension for RADIUS Authorization . . . . . . . 7
6.1.2.1. Dynamic Update of VACM and Extended VACM MIB
Module Objects . . . . . . . . . . . . . . . . . . 7
6.1.2.2. Purging Volatile Entries in the Extended VACM
MIB Module . . . . . . . . . . . . . . . . . . . . 9
6.1.3. Elements of Procedure for Extended VACM . . . . . . . 9
6.2. MIB modules required for IMPORTS . . . . . . . . . . . . . 10
7. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 11
8. Security Considerations . . . . . . . . . . . . . . . . . . . 15
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 16
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
11.1. Normative References . . . . . . . . . . . . . . . . . . . 17
11.2. Informative References . . . . . . . . . . . . . . . . . . 17
Appendix A. Open Issues . . . . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
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1. Introduction
This memo specifies an integration of several protocols to
operationally simplify the administration of the access rights
granted to users of network management data. In this environment:
o The View-Based Access Control Model (VACM) [RFC3415] provides a
means to manage users' access rights to management information
accessed using SNMP.
o The Simple Network Management Protocol version 3 (SNMPv3) provides
message security services through the Security Subsystem.
o The Transport Subsystem for the Simple Network Management Protocol
[RFC5590] defines a Transport Subsystem.
o The Transport Security Model for SNMP [RFC5591] defines a
Transport Security Model.
o The Secure Shell Transport Model for SNMP [RFC5592] defines a
Secure Shell Transport Model and Remote Authentication Dial-In
User Service (RADIUS).
o RADIUS Usage for Simple Network Management Protocol (SNMP)
Transport Models [RFC5608] defines a method for authenticating
SNMPv3 users via RADIUS.
It is possible to authenticate SNMPv3 messages via a RADIUS when
those messages are sent over the SSH transport. As originally
envisioned, VACM authorizes a given SNMP transaction using on-device,
pre-existing authorization configuration. In order to leverage a
centralized RADIUS service to its full extent, the access control
decision in the Access Control Subsystem needs to be able to make use
of authorization information received from RADIUS as well. This
document defines an extension to the View-based Access Control Model
to obtain authorization information for an authenticated principal,
from RADIUS.
Additional introductory material on the RADIUS operational model and
RADIUS usage with SNMP may be found in Sections 1.3 and 1.5 of
[RFC5608].
It is important to understand the SNMP architecture and the
terminology of the architecture to understand where the Extended
View-based Access Control Model described in this memo fits into the
architecture and how it interacts with other subsystems and models
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within the architecture. It is expected that reader will have also
read and understood RFC3411 [RFC3411], RFC3412 [RFC3412], RFC3413
[RFC3413], RFC3415 [RFC3415]and RFC3418 [RFC3418]. As this document
describes an extension to VACM, a thorough understanding of RFC3415
[RFC3415] is assumed.
2. The Internet-Standard Management Framework
For a detailed overview of the documents that describe the current
Internet-Standard Management Framework, please refer to section 7 of
RFC 3410 [RFC3410].
Managed objects are accessed via a virtual information store, termed
the Management Information Base or MIB. MIB objects are generally
accessed through the Simple Network Management Protocol (SNMP).
Objects in the MIB are defined using the mechanisms defined in the
Structure of Management Information (SMI). This memo specifies a MIB
module that is compliant to the SMIv2, which is described in STD 58,
RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58, RFC 2580
[RFC2580].
3. Conventions
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].
4. Overview
4.1. System Block Diagram
A block diagram of the major system components referenced in this
document may be useful to understanding the text that follows.
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+--------+
+......................... |RADIUS |....+
. |Server | .
Shared +--------+ .
User | .
Credentials RADIUS | Shared
. | RADIUS
. | Secret
. | .
+-------------+ +-----------------+
| Network | | RADIUS Client / |
| Management | SNMP | SNMP Engine / |
| Application |------------------| Network Device |
+-------------+ SSH +-----------------+
Block Diagram
This diagram illustrates that a network management application
communicates with a network device, the managed entity, using SNMP
over SSH. The network devices uses RADIUS to communicate with a
RADIUS Server to authenticate the network management application (or
the user whose credentials that application provides) and to obtain
authorization information related to access via SNMP for purpose of
device management. Other secure transport protocols might be used
instead of SSH.
4.2. Using RADIUS with SNMP
There are two use cases for RADIUS support of management access via
SNMP. These are (a) service authorization and (b) access control
authorization. RADIUS almost always involves user authentication as
prerequisite to authorization, and there is a user authentication
phase for each of these two use cases. The first use case is
discussed in detail in [RFC5608]. The second use case is the subject
of this document. This document describes how RADIUS attributes and
messages are applied to the specific application area of SNMP Access
Control Models, and VACM in particular.
This document assumes that Extended VACM will be used in conjunction
with an SNMP secure Transport Model and the SNMP Transport Security
Model. The rationale for this assumption is as follows. The RFC
3411 SNMP architecture maintains strong modularity and separation of
concerns, extending to separating user identity (authentication) from
user database access rights (authorization). The former is the
business of the Security Subsystem and the latter is the business of
the Access Control Subsystem. RADIUS, on the other hand, allows for
no such separation of authorization from authentication. In order to
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use RADIUS with SNMP, binding of user authentication to user
authorization must be achieved, without violating the modularity of
the RFC 3411 SNMP architecture.
RADIUS does support a limited form of Authorize-Only operations. The
RADIUS "Authorize Only" Service-Type Attribute can be specified in an
Access-Request message, but only when accompanied by a RADIUS State
Attribute, which contains an implementation specific "cookie"
representing the successful outcome of a previous authentication
transaction. For that reason, it is not possible to completely
separate the use of RADIUS by the Access Control Subsystem from the
use of RADIUS by other subsystems. This suggests that the most
straightforward approach is to leverage the existing RADIUS usage, as
documented in [RFC5608], and the tmStateReference cache, as
documented in Section 5.2 of [RFC5590].
This document also assumes that the detailed access control rules are
pre-configued in the NAS. Dynamic user authorization for MIB
database access control, as defined herein, is limited to mapping the
authenticated user to a pre-existing group, which in turn is mapped
to the pre-existing rules. The operative use case assumption is that
roles within an organization (i.e. groups and rules) change
infrequently while the users assigned to those roles change much more
frequently. It is the user to role mapping that is outsourced to the
RADIUS server.
5. Structure of the MIB Module
5.1. Textual Conventions
This MIB module makes use of the SnmpAdminString and
SnmpSecurityModel textual conventions.
5.2. The extVacmCounters Subtree
The extVacmCounters subtree contains all of this module's counters.
5.3. The Notifications Subtree
No notifications are defined in this MIB module
5.4. The Table Structures
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6. Relationship to Other MIB Modules
6.1. Relationship to the VACM MIB
6.1.1. Extended VACM for RADIUS Authorization
This document will rely on implementation specific integration of the
RADIUS client for user authentication and authorization. Further, it
will rely on implementation specific caching of MIB database access
policy information, in the form of the RADIUS Management-Policy-Id
Attribute, such that it will be available to Extended VACM.
A NAS that is compliant to this specification, MUST treat any RADIUS
Access-Accept message that provisions a specific policy for MIB
database access control that cannot be provided as if an Access-
Reject message had been received instead.
The RADIUS Management-Policy-Id Attribute MUST be used in an Access-
Accept message to provision a user-specific access control policy for
use in conjunction with Extended VACM. The syntax and semantics of
the Management-Policy-Id attribute are described in Section 6.3 of
[RFC5607].
The intended use of the content of the Management-Policy-Id attribute
is to provision a mapping between the authenticated user, associated
with the secure transport session, and an access control group pre-
provisioned in the VACM MIB module. Details of this mapping are
described in following sections.
6.1.2. VACM Extension for RADIUS Authorization
The extension to VACM [RFC3415] described in this document is a
method for one or more of its MIB module objects to be dynamically
provisioned based on information received from RADIUS, or some
similar AAA service. This extension requires no changes to the
Abstract Service Interface (ASI) for the Access Control Subsystem,
nor any changes in the Elements of Procedure (EOP) for VACM. A new
MIB module that augments the vacmSecurityToGroupTable is defined in
this document, as well as supplemental EOP for Extended VACM to
follow. It does require that a module of code somewhere in the NAS
be able to write to the VACM MIB module and Extended VACM MIB Module,
and that it reliably and consistently do so in immediate response to
access control policy information received from RADIUS.
6.1.2.1. Dynamic Update of VACM and Extended VACM MIB Module Objects
The implementation-dependent interface between the RADIUS Client
function and the SNMP Engine is responsible for updating the
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extVacmSecurityToGroupTable and the corresponding rows of the
vacmSecurityToGroupTable table within the VACM MIB Module [RFC3415]
and Specifically, the RADIUS User-Name Attribute is used as the
vacmSecurityName and the RADIUS Management-Policy-Id Attribute is
used as the vacmGroupName. The value used for vacmSecurityModel is
the registered value for the security model in use. Note that the
security model SHOULD be one which binds principal identity to access
control policy via an external AAA server, such as the Transport
Security Model. To do otherwise potentially creates a security risk.
In creating a row entry in the vacmSecurityToGroupTable, there are
three cases to consider:
o No existing row has a matching vacmSecurityModel and
vacmSecurityName.
o An existing row has a matching vacmSecurityModel and
vacmSecurityName.
o No additional rows can be created, e.g. because of resource
constraints, etc.
The second and third cases require special consideration. The second
case may represent a conflict between dynamic access control
authorization from RADIUS and local access control configuration by a
security administrator. If one assumes that the security
administrator intentionally configured a table entry for the
"conflicting" vacmSecurityModel / vacmSecurityName pair, with full
knowledge that it might over-ride dynamic authorization information
from RADIUS, the right thing to do would be nothing. That is to say,
do not update the table based on RADIUS authorization information.
On the other hand, it is possible that the "name collision" is the
result of a mistake, or the result of stale configuration
information.
The behavior specified for Extended VACM is to make no update to the
vacmSecurityToGroupTable in this case, and to increment the
extVacmSecurityNameConflict counter.
The third case is likely to be rare, and SHOULD result in a
notification of some sort being logged for action by the system
administrator.
It is expected that the value of the RADIUS Management-Policy-Id
Attribute match an existing vacmGroupName that can be sucessfully
used as an index to the vacmAccessTable. If no matching
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vacmGroupName exists, then the access control defaults to this will
result in the default access rights of "no access", which is the
desired result. The NAS should increment the extVacmMissingGroupName
counter, for troubleshooting purposes, as this most likely indicates
an administrative misconfiguration.
In addition to creating a new row in the vacmSecurityToGroupTable,
the NAS creates a corresponding new row in the
extVacmSecurityToGroupTable, using the same index values as were used
to create the row in the vacmSecurityToGroupTable, along with an
appropriate extVacmTransportSessionID. The value of
extVacmRowLifetime is set to the value of the RADIUS Session-Timeout
Attribute, if one was received by the RADIUS Client for this session,
or to zero (0) otherwise.
6.1.2.2. Purging Volatile Entries in the Extended VACM MIB Module
Entries in the vacmSecurityToGroupTable MUST NOT persist across
system reboots.
When the secure transport session is torn down, disconnected or times
out, the corresponding extVacmSecurityToGroupEntry is deleted. When
no rows remain having corresponding values for extVacmSecurityName
and extVacmSecurityModel, then, if the corresponding row in the in
the vacmSecurityToGroup has a StorageType of "volatile", that row
MUST be removed as well. The mechanism to accomplish this task is
implementation specific.
6.1.3. Elements of Procedure for Extended VACM
This section describes the Elements of Procedure for Extended VACM.
The function of the VACM extension is to manage the creation and
deletion of rows in the vacmSecurityToGroupTable, based on the
outcome of RADIUS authorization. All access control decision
functions are taken by VACM, as defined in [RFC3415]. The elements
of procedure for VACM are unchanged.
When a RADIUS (or other AAA service) authorizes SNMP data access
control for a user-authenticated secure transport session, the NAS
causes the RADIUS provisioning information to be made available to
the Extended VACM facility, which populates the
vacmSecurityToGroupTable, as follows:
1. If the the RADIUS Management-Policy-Id Attribute is not
available, increment the extVacmNoPolicy counter. Do not create
a table row.
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2. If the the RADIUS Management-Policy-Id Attribute is available,
and if no existing row has a vacmSecurityName matching the RADIUS
User-Name Attribute and vacmSecurityModel corresponding to the
security model in use, create a new row with the columns
populated as follows:
A. extVacmTransportSessionID = ID provided by the Secure
Transport Model
B. vacmSecurityModel = value of SnmpSecurityModel registered
with the security model in use
C. vacmSecurityName = RADIUS User-Name Attribute
D. vacmGroupName = RADIUS Management-Policy-Id Attribute
E. extVacmRowLifetime = RADIUS Session-Timeout Attribute if
available, otherwise zero (0)
3. If an existing row has a vacmSecurityName matching the RADIUS
User-Name Attribute, a vacmSecurityModel corresponding to the
security model, and an extVacmTransportSessionID matching the ID
provided by the Secure Transport, increment the
extVacmSecurityNameConflict counter. Do not create a table row.
4. If no additional table rows can be created, e.g. because of
resource constraints, increment the extVacmResourceError counter.
When a RADIUS-authenticated secure transport session is disconnected
by the remote peer, the NAS causes the Extended VACM to remove the
corresponding table row from the vacmSecurityToGroupTable. The NAS
provides an implementation dependent identifier of the session in
question to Extended VACM.
1. Search for a row with a matching extVacmTransportSessionID.
2. If a table row exists with a matching value of
extVACMTransportSessionID, that row is deleted.
6.2. MIB modules required for IMPORTS
The MIB module defined employs textual conventions from [RFC2579] and
[RFC3411].
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7. Definitions
SNMP-EXT-VACM-MIB DEFINITIONS ::= BEGIN
IMPORTS
MODULE-COMPLIANCE, OBJECT-GROUP FROM SNMPv2-CONF
MODULE-IDENTITY, OBJECT-TYPE,
mib-2,
Unsigned32,
Counter32 FROM SNMPv2-SMI
SnmpAdminString,
SnmpSecurityModel FROM SNMP-FRAMEWORK-MIB;
snmpExtVacmMIB MODULE-IDENTITY
LAST-UPDATED "201001290000Z" -- 29 January, 2010
ORGANIZATION "ISMS Working Group"
CONTACT-INFO "WG-email: isms@ietf.org"
DESCRIPTION "The management and local datstore information
definitions for the Extended View-based Access
Control Model for SNMP.
Copyright (c) 2010 IETF Trust and the persons
identified as the document authors. 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 MIB module is part of RFC XXXX;
see the RFC itself for full legal notices."
REVISION "201001290000Z"
DESCRIPTION "Initial version,published as RFC XXXX."
::= { mib-2 XXX }
extVacmMIBObjects OBJECT IDENTIFIER ::= { snmpExtVacmMIB 1 }
extVacmMIBConformance OBJECT IDENTIFIER ::= {snmpExtVacmMIB 2 }
extVacmCounters OBJECT IDENTIFIER ::= { extVacmMIBObjects 1 }
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extVacmResourceError OBJECT-TYPE
SYNTAX Counter32
UNITS "lost rows"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of VACM Security Name to Security
Group table rows that could not be created by
Extended VACM because of insufficient resources."
::= { extVacmCounters 1 }
extVacmNoPolicy OBJECT-TYPE
SYNTAX Counter32
UNITS "lost rows"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of VACM Security Name to Security
Group table rows that could not be created by
Extended VACM because the AAA-provisioned
group policy did not match an existing row in
the VACM access table."
::= { extVacmCounters 2 }
extVacmSecurityNameConflict OBJECT-TYPE
SYNTAX Counter32
UNITS "lost rows"
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The number of VACM Security Name to Security
Group table rows that could not be created by
Extended VACM because the AAA-provisioned
security name (user name) conflicted with an
existing row in the table."
::= { extVacmCounters 3 }
extVacmSecurityToGroupTable OBJECT-TYPE
SYNTAX SEQUENCE OF ExtVacmSecurityToGroupEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION "This table maps a combination of securityModel and
securityName into a groupName which is used to define
an access control policy for a group of principals."
::= { extVacmMIBObjects 2 }
extVacmSecurityToGroupEntry OBJECT-TYPE
SYNTAX ExtVacmSecurityToGroupEntry
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MAX-ACCESS not-accessible
STATUS current
DESCRIPTION "An entry in this table maps the combination of a
securityModel and securityName into a groupName.
Entries do not persist across reboots."
INDEX {
extVacmSecurityModel,
extVacmSecurityName,
extVacmTransportSessionID
}
::= { extVacmSecurityToGroupTable 1 }
ExtVacmSecurityToGroupEntry ::= SEQUENCE
{
extVacmSecurityModel SnmpSecurityModel,
extVacmSecurityName SnmpAdminString,
extVacmTransportSessionID Unsigned32,
extVacmGroupName SnmpAdminString,
extVacmRowLifetime Unsigned32
}
extVacmSecurityModel OBJECT-TYPE
SYNTAX SnmpSecurityModel(1..2147483647)
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION "The Security Model, by which the vacmSecurityName
referenced by this entry is provided.
This object cannot take the 'any' (0) value."
::= { extVacmSecurityToGroupEntry 1 }
extVacmSecurityName OBJECT-TYPE
SYNTAX SnmpAdminString (SIZE(1..32))
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION "The Security Name of a principal, represented in a
Security Model independent format which is mapped by
this entry to a groupName."
::= { extVacmSecurityToGroupEntry 2 }
extVacmTransportSessionID OBJECT-TYPE
SYNTAX Unsigned32
MAX-ACCESS read-create
STATUS current
DESCRIPTION "An identifier of the secure transport
model's session associated with this
authenticated user. The identifier
MUST be unique within the scope of the NAS.
It's content is implementation dependant
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and it SHOULD be used merely as an index."
::= { extVacmSecurityToGroupEntry 3 }
extVacmGroupName OBJECT-TYPE
SYNTAX SnmpAdminString (SIZE(1..32))
MAX-ACCESS read-create
STATUS current
DESCRIPTION "The name of the group to which this entry
is to belong. This information would have come
from, for example, the RADIUS Management-Policy-ID
attribute.
This group name is used to set the vacmGroupName
in the corresponding vacmSecurityToGroupEntry."
::= { extVacmSecurityToGroupEntry 4 }
extVacmRowLifetime OBJECT-TYPE
SYNTAX Unsigned32
UNITS "seconds"
MAX-ACCESS read-create
STATUS current
DESCRIPTION "The number of seconds remaining in this row's
lifetime. Extended VACM SHOULD delete this
row when this value transitions from non-zero to
zero. The initial value comes from, for example,
the RADIUS Session-Timeout attribute. If that
information is unavailable, the initial value
is zero."
::= { extVacmSecurityToGroupEntry 5 }
-- Conformance information ******************************************
extVacmMIBCompliances
OBJECT IDENTIFIER ::= {extVacmMIBConformance 1}
extVacmMIBGroups
OBJECT IDENTIFIER ::= {extVacmMIBConformance 2}
-- compliance statements
extVacmMIBBasicCompliance MODULE-COMPLIANCE
STATUS current
DESCRIPTION "The compliance statement for SNMP engines which
implement the Extensions to the View-based Access
Control Model for use with RADIUS.
"
MODULE -- this module
MANDATORY-GROUPS { extVacmGroup }
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::= { extVacmMIBCompliances 1 }
-- units of conformance
extVacmGroup OBJECT-GROUP
OBJECTS {
extVacmResourceError,
extVacmNoPolicy,
extVacmSecurityNameConflict,
extVacmGroupName,
extVacmRowLifetime,
extVacmTransportSessionID
}
STATUS current
DESCRIPTION "A collection of objects for supporting the use
of RADIUS to provide user / group mappings for VACM.
"
::= { extVacmMIBGroups 1 }
END
8. Security Considerations
TODO
Some of the readable objects in this MIB module (i.e., objects with a
MAX-ACCESS other than not-accessible) may be considered sensitive or
vulnerable in some network environments. It is thus important to
control even GET and/or NOTIFY access to these objects and possibly
to even encrypt the values of these objects when sending them over
the network via SNMP. These are the tables and objects and their
sensitivity/vulnerability:
o TBD
SNMP versions prior to SNMPv3 did not include adequate security.
Even if the network itself is secure (for example by using IPsec),
even then, there is no control as to who on the secure network is
allowed to access and GET/SET (read/change/create/delete) the objects
in this MIB module.
It is RECOMMENDED that implementers consider the security features as
provided by the SNMPv3 framework (see [RFC3410], section 8),
including full support for the SNMPv3 cryptographic mechanisms (for
authentication and privacy).
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Further, deployment of SNMP versions prior to SNMPv3 is NOT
RECOMMENDED. Instead, it is RECOMMENDED to deploy SNMPv3 and to
enable cryptographic security. It is then a customer/operator
responsibility to ensure that the SNMP entity giving access to an
instance of this MIB module is properly configured to give access to
the objects only to those principals (users) that have legitimate
rights to indeed GET or SET (change/create/delete) them.
9. IANA Considerations
The MIB module in this document uses the following IANA-assigned
OBJECT IDENTIFIER values recorded in the SMI Numbers registry:
Descriptor OBJECT IDENTIFIER value
---------- -----------------------
snmpExtVacmMIB { mib-2 XXX }
Editor's Note (to be removed prior to publication): the IANA is
requested to assign a value for "XXX" under the 'mib-2' subtree and
to record the assignment in the SMI Numbers registry. When the
assignment has been made, the RFC Editor is asked to replace "XXX"
(here and in the MIB module) with the assigned value and to remove
this note.
10. Contributors
The following participants from the isms working group contributed to
the development of this document:
o David Harrington
o Juergen Schoenwaelder
o Tom Petch
o Wes Hardaker
11. References
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11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2578] McCloghrie, K., Ed., Perkins, D., Ed., and J.
Schoenwaelder, Ed., "Structure of Management Information
Version 2 (SMIv2)", STD 58, RFC 2578, April 1999.
[RFC2579] McCloghrie, K., Ed., Perkins, D., Ed., and J.
Schoenwaelder, Ed., "Textual Conventions for SMIv2",
STD 58, RFC 2579, April 1999.
[RFC2580] McCloghrie, K., Perkins, D., and J. Schoenwaelder,
"Conformance Statements for SMIv2", STD 58, RFC 2580,
April 1999.
[RFC3411] Harrington, D., Presuhn, R., and B. Wijnen, "An
Architecture for Describing Simple Network Management
Protocol (SNMP) Management Frameworks", STD 62, RFC 3411,
December 2002.
[RFC3415] Wijnen, B., Presuhn, R., and K. McCloghrie, "View-based
Access Control Model (VACM) for the Simple Network
Management Protocol (SNMP)", STD 62, RFC 3415,
December 2002.
[RFC5590] Harrington, D. and J. Schoenwaelder, "Transport Subsystem
for the Simple Network Management Protocol (SNMP)",
RFC 5590, June 2009.
[RFC5591] Harrington, D. and W. Hardaker, "Transport Security Model
for the Simple Network Management Protocol (SNMP)",
RFC 5591, June 2009.
[RFC5607] Nelson, D. and G. Weber, "Remote Authentication Dial-In
User Service (RADIUS) Authorization for Network Access
Server (NAS) Management", RFC 5607, July 2009.
[RFC5608] Narayan, K. and D. Nelson, "Remote Authentication Dial-In
User Service (RADIUS) Usage for Simple Network Management
Protocol (SNMP) Transport Models", RFC 5608, August 2009.
11.2. Informative References
[RFC3410] Case, J., Mundy, R., Partain, D., and B. Stewart,
"Introduction and Applicability Statements for Internet-
Standard Management Framework", RFC 3410, December 2002.
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[RFC3412] Case, J., Harrington, D., Presuhn, R., and B. Wijnen,
"Message Processing and Dispatching for the Simple Network
Management Protocol (SNMP)", STD 62, RFC 3412,
December 2002.
[RFC3413] Levi, D., Meyer, P., and B. Stewart, "Simple Network
Management Protocol (SNMP) Applications", STD 62,
RFC 3413, December 2002.
[RFC3418] Presuhn, R., "Management Information Base (MIB) for the
Simple Network Management Protocol (SNMP)", STD 62,
RFC 3418, December 2002.
[RFC5592] Harrington, D., Salowey, J., and W. Hardaker, "Secure
Shell Transport Model for the Simple Network Management
Protocol (SNMP)", RFC 5592, June 2009.
Appendix A. Open Issues
This section identifies questions and issues that have not been
addressed in this version of this document. This section will
probably be removed prior to publication, since there will be no
questions left to address.
1. Is this document an amendment or update to RFC 3514? Or is it
simply a standalone document that describes how to provision
certain MIB Objects defined in RFC 3514, along with an extended
set of augmenting table columns?
2. Does this document need to make any reference to the Elements of
Procedure in RFC 3514, or does is simply need its own Elements of
Procedure for updating the group mapping table?
3. Dave Harrington had issued a summary email after IETF75
containing apparently contradictory statements about whether the
additional columns should be in the *same* table that VACM uses
or in another, separate table that augments the VACM table.
Basically, we need some help in actually structuring the new MIB
Module.
4. The Groups and Conformance sections of the MIB Module need to be
checked and kept in alignment with the definitions.
5. Make sure that the new Elements of Procedure make sense and cover
all the corner cases correctly.
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6. for session tracking use tlstmSessionID?
7. Security considerations need to be filled in, specifically
concerning trust relationships to RADIUS and the interaction with
statically configured policy.
Authors' Addresses
Kaushik Narayan
Cisco Systems, Inc.
10 West Tasman Drive
San Jose, CA 95134
USA
Phone: +1.408.526.8168
Email: kaushik_narayan@yahoo.com
David Nelson
Elbrys Networks, Inc.
282 Corporate Drive, Unit #1,
Portsmouth, NH 03801
USA
Phone: +1.603.570.2636
Email: d.b.nelson@comcast.net
Randy Presuhn (editor)
None
Email: randy_presuhn@mindspring.com
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