Cisco Nexus 7000 Series NX-OS Security Configuration Guide, Release 4.1

Configuring User Accounts and RBAC

This chapter describes how to configure user accounts and role-based access control (RBAC) on NX-OS devices.

This chapter includes the following sections:

•Information About User Accounts and RBAC

•Licensing Requirements for User Accounts and RBAC

•Guidelines and Limitations

•Enabling Password-Strength Checking

•Configuring User Accounts

•Configuring Roles

•Verifying User Accounts and RBAC Configuration

•Example User Accounts and RBAC Configuration

•Default Settings

•Additional References

•Feature History for User Accounts and RBAC

Information About User Accounts and RBAC

You can create and manage users accounts and assign roles that limit access to operations on the NX-OS device. RBAC allows you to define the rules for an assign role that restrict the authorization that the user has to access management operations.

This section includes the following topics:

•About User Accounts

•Characteristics of Strong Passwords

•About User Roles

•About User Role Rules

•User Role Configuration Distribution

•Virtualization Support

About User Accounts

You can configure up to a maximum of 256 user accounts. By default, the user account does not expire unless you explicitly configure it to expire. The expire option determines the date when the user account is disabled.

Users can have user accounts on multiple VDCs. These users can move between VDCs after an initial connection to a VDC.

The Cisco NX-OS software provides two default user accounts, admin and adminbackup.

Tip The following words are reserved and cannot be used to configure users: bin, daemon, adm, lp, sync, shutdown, halt, mail, news, uucp, operator, games, gopher, ftp, nobody, nscd, mailnull, root, rpc, rpcuser, xfs, gdm, mtsuser, ftpuser, man, and sys.

Note User passwords are not displayed in the configuration files.

Caution The Cisco NX-OS software does not support all numeric usernames, whether created with TACACS+ or RADIUS, or created locally. Local users with all numeric names cannot be created. If an all numeric user name exists on an AAA server and is entered during login, the user is not logged in.

Characteristics of Strong Passwords

A strong password has the following characteristics:

•At least eight characters long

•Does not contain many consecutive characters (such as "abcd")

•Does not contain many repeating characters (such as "aaabbb")

•Does not contain dictionary words

•Does not contain proper names

•Contains both uppercase and lowercase characters

•Contains numbers

The following are examples of strong passwords:

•If2CoM18

•2004AsdfLkj30

•Cb1955S21

Note Clear text passwords cannot contain dollar signs ($) or spaces anywhere in the password. Also, they cannot include these special characters at the beginning of the password: quotation marks (" or '), vertical bars (|), or right angle brackets (>).

Tip If a password is trivial (such as a short, easy-to-decipher password), the NX-OS software will reject your password configuration if password-strength checking is enabled (see the "Enabling Password-Strength Checking" section). Be sure to configure a strong password as shown in the sample configuration. Passwords are case sensitive.

About User Roles

User roles contain rules that define the operations allowed for the user who is assigned the role. Each user role can contain multiple rules and each user can have multiple roles. For example, if role1 allows access only to configuration operations, and role2 allows access only to debug operations, then users who belong to both role1 and role2 can access configuration and debug operations. You can also limit access to specific VLANs, virtual routing and forwarding instances (VRFs), and interfaces.

The Cisco NX-OS software provides four default user roles:

•network-admin—Complete read-and-write access to the entire NX-OS device (only available in the default VDC)

•network-operator—Complete read access to the entire NX-OS device (only available in the default VDC)

•vdc-admin—Read-and-write access limited to a VDC

•vdc-operator—Read access limited to a VDC

Note You cannot change the default user roles.

You can create custom roles within a VDC. By default, the user roles that you create allow access only to the show, exit, end, and configure terminal commands. You must add rules to allow users to display or configure features.

The VDCs do not share user roles. Each VDC maintains an independent user role database. Within a VDC, roles are configured by rule and attribute assignment.

Note If you belong to multiple roles, you can execute a combination of all the commands permitted by these roles. Access to a command takes priority over being denied access to a command. For example, suppose a user has RoleA, which denied access to the configuration commands. However, the user also has RoleB, which has access to the configuration commands. In this case, the user has access to the configuration commands.

About User Role Rules

The rule is the basic element of a role. A rule defines what operations the role allows the user to perform. You can apply rules for the following parameters:

•Command—A command or group of commands defined in a regular expression.

•Feature—Commands that apply to a function provided by the NX-OS software.

•Feature group—Default or user-defined group of features.

These parameters create a hierarchical relationship. The most basic control parameter is the command. The next control parameter is the feature, which represents all commands associated with the feature. The last control parameter is the feature group. The feature group combines related features and allows you to easily manage the rules. The NX-OS software also supports the predefined feature group L3 that you can use.

You can configure up to 256 rules for each role. The user-specified rule number determines the order in which the rules are applied. Rules are applied in descending order. For example, if a role has three rules, rule 3 is applied before rule 2, which is applied before rule 1.

User Role Configuration Distribution

Cisco Fabric Services (CFS) allows the NX-OS device distribute the user role configuration to other NX-OS devices in the network. When you enable CFS distribution for a feature on your device, the device belongs to a CFS region containing other devices in the network that you have also enabled for CFS distribution for the feature. CFS distribution for the user role feature is disabled by default.

Note You must explicitly enable CFS for user role on each device to which you want to distribute configuration changes.

After you enable CFS distribution for user role on your NX-OS device, the first user role configuration command that you enter causes the NX-OS software to take the following actions:

•Creates a CFS session on your NX-OS device.

•Locks the user role configuration on all NX-OS devices in the CFS region with CFS enabled for the user role feature.

•Saves the user role configuration changes in a temporary buffer on the NX-OS device.

The changes stay in the temporary buffer on the NX-OS device until you explicitly commit them to be distributed to the devices in the CFS region. When you commit the changes, the NX-OS software takes the following actions:

•Applies the changes to the running configuration on your NX-OS device.

•Distributes the updated user role configuration to the other NX-OS devices in the CFS region.

•Unlocks the user role configuration in the devices in the CFS region.

•Terminates the CFS session.

For detailed information on CFS, see the Cisco Nexus 7000 Series NX-OS System Management Configuration Guide, Release 4.1.

Virtualization Support

The users with the network-admin and network-operator roles can operate in all virtual device contexts (VDCs) when logged in from the default VDC and use the switchto vdc command to access other VDCs. All other user roles are local to the VDC. Roles are not shared between VDCs. Each VDC maintains an independent user role database. For more information on VDCs, see the Cisco Nexus 7000 Series NX-OS Virtual Device Context Configuration Guide, Release 4.1.

Licensing Requirements for User Accounts and RBAC

The following table shows the licensing requirements for this feature:

Guidelines and Limitations

User accounts and RBAC have the following configuration guidelines and limitations:

•You can create up to 64 user-defined roles in a VDC in addition to the four default user roles in the default VDC and the two default user roles in the nondefault VDCs.

•You can add up to 256 rules to a user role.

•You can add up to 64 user-defined feature groups to a VDC in addition to the default feature group, L3.

•You can configure up to 256 users in a VDC.

•You can assign a maximum of 64 user roles to a user account.

•If you have a user account configured on the local Cisco NX-OS device that has the same name as a remote user account on an AAA server, the Cisco NX-OS software applies the user roles for the local user account to the remote user, not the user roles configured on the AAA server.

•You cannot delete the default admin or adminbackup user account.

•You cannot remove the default user roles from the default admin or adminbackup user account.

•You cannot change the default user roles network-admin, vdc-admin, network-operator, and vdc-operator.

Note If you are familiar with the Cisco IOS CLI, be aware that the Cisco NX-OS commands for this feature might differ from the Cisco IOS commands that you would use.

Note A user account must have at least one user role.

Enabling Password-Strength Checking

You can enable password-strength checking which prevents you from creating weak passwords for user accounts. For information about strong passwords, see the "Characteristics of Strong Passwords" section.

BEFORE YOU BEGIN

Ensure that you are in the desired VDC (or use the switchto vdc command).

SUMMARY STEPS

1. configure terminal

2. password strength-check

3. exit

4. show password strength-check

5. copy running-config startup-config

DETAILED STEPS

Configuring User Accounts

You can create a maximum of 256 user accounts on an NX-OS device. User accounts have the following attributes:

•Username

•Password

•Expiry date

•User roles

You can enter the password in clear text format or encrypted format. The Cisco NX-OS password encrypts clear text passwords before saving them to the running configuration. Encrypted format passwords are saved to the running configuration without further encryption.

User accounts can have a maximum of 64 user roles. For more information on user roles, see the "Configuring Roles" section.

User accounts are local to a VDC. However, users with the network-admin or network-operator role can log in to the default VDC and access other VDCs using the switchto vdc command.

Note Changes to user account attributes do not take effect until the user logs in and creates a new session.

Note You cannot delete the default admin user account. You can create another account with the network-admin or vdc-admin role.

BEFORE YOU BEGIN

Ensure that you are in the desired VDC (or use the switchto vdc command).

SUMMARY STEPS

1. configure terminal

2. show role

3. username user-id [password [0 | 5]password] [expire date] [role role-name]

4. exit

5. show user-account

6. copy running-config startup-config

DETAILED STEPS

Configuring Roles

This section includes the following topics:

•Enabling User Role Configuration Distribution

•Creating User Roles and Rules

•Creating Feature Groups

•Changing User Role Interface Policies

•Changing User Role VLAN Policies

•Changing User Role VRF Policies

•Distributing the User Role Configuration

•Discarding the User Role Distribution Session

•Clearing the User Role Distribution Session

Enabling User Role Configuration Distribution

To distribute the user roles configuration to other NX-OS devices in the network, you must first enable CFS distribution for user roles.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

SUMMARY STEPS

1. configure terminal

2. role distribute

3. exit

4. show role session status

5. copy running-config startup-config

DETAILED STEPS

Creating User Roles and Rules

You can configure up to 64 user roles in a VDC. Each user role can have up to 256 rules. You can assign a user role to more that one user account.

The rule number that you specify determines the order in which the rules are applied. Rules are applied in descending order. For example, if a role has three rules, rule 3 is applied before rule 2, which is applied before rule 1.

BEFORE YOU BEGIN

Ensure that you are in the desired VDC (or use the switchto vdc command).

If you want to distribute the user role configuration, enable user role configuration distribution on all NX-OS devices to which you want the configuration distributed (see the "Distributing the User Role Configuration" section)

SUMMARY STEPS

1. configure terminal

2. role name role-name

3. rule number {deny | permit} command command-string

rule number {deny | permit} {read | read-write}

rule number {deny | permit} {read | read-write} feature feature-name

rule number {deny | permit} {read | read-write} feature-group group-name

4. description text

5. exit

6. show role

7. show role {pending | pending-diff}

8. role commit

9. copy running-config startup-config

DETAILED STEPS

Creating Feature Groups

You can create custom feature groups to add to the default list of features provided by the Cisco NX-OS software. These groups contain one or more of the features. You can create up to 64 feature groups in a VDC.

Note You cannot change the default feature group L3.

BEFORE YOU BEGIN

Ensure that you are in the desired VDC (or use the switchto vdc command).

If you want to distribute the user role configuration, enable user role configuration distribution on all NX-OS devices to which you want the configuration distributed (see the "Distributing the User Role Configuration" section)

SUMMARY STEPS

1. configure terminal

2. role feature-group group-name

3. feature feature-name

4. exit

5. show role feature-group

6. show role {pending | pending-diff}

7. role commit

8. copy running-config startup-config

DETAILED STEPS

Changing User Role Interface Policies

You can change a user role interface policy to limit the interfaces that the user can access. By default, a user role allows access to all interfaces in the VDC.

Note You cannot change the default roles network-admin, network-operator, vdc-admin, and vdc-operator.

BEFORE YOU BEGIN

Ensure that you are in the desired VDC (or use the switchto vdc command).

Create one or more user roles (see the "Creating User Roles and Rules" section).

If you want to distribute the user role configuration, enable user role configuration distribution on all NX-OS devices to which you want the configuration distributed (see the "Distributing the User Role Configuration" section)

SUMMARY STEPS

1. configure terminal

2. role name role-name

3. interface policy deny

4. permit interface interface-list

5. exit

6. show role

7. show role {pending | pending-diff}

8. role commit

9. copy running-config startup-config

DETAILED STEPS

Changing User Role VLAN Policies

You can change a user role VLAN policy to limit the VLANs that the user can access. By default, a user role allows access to all VLANs in the VDC.

Note You cannot change the default roles network-admin, network-operator, vdc-admin, and vdc-operator.

BEFORE YOU BEGIN

Ensure that you are in the desired VDC (or use the switchto vdc command).

Create one or more user roles (see the "Creating User Roles and Rules" section).

If you want to distribute the user role configuration, enable user role configuration distribution on all NX-OS devices to which you want the configuration distributed (see the "Distributing the User Role Configuration" section)

SUMMARY STEPS

1. configure terminal

2. role name role-name

3. vlan policy deny

4. permit vlan vlan-range

5. exit

6. show role

7. show role {pending | pending-diff}

8. role commit

9. copy running-config startup-config

DETAILED STEPS

Changing User Role VRF Policies

You can change a user role VRF policy to limit the VRFs that the user can access. By default, a user role allows access to all VRFs in the VDC.

Note You cannot change the default roles network-admin, network-operator, vdc-admin, and vdc-operator.

BEFORE YOU BEGIN

Ensure that you are in the desired VDC (or use the switchto vdc command).

Create one or more user roles (see the "Creating User Roles and Rules" section).

If you want to distribute the user role configuration, enable user role configuration distribution on all NX-OS devices to which you want the configuration distributed (see the "Distributing the User Role Configuration" section)

SUMMARY STEPS

1. configure terminal

2. role name role-name

3. vrf policy deny

4. permit vrf vrf-name

5. exit

6. show role

7. show role {pending | pending-diff}

8. role commit

9. copy running-config startup-config

DETAILED STEPS

Distributing the User Role Configuration

You can distribute the user role configuration stored in the temporary buffer to the running configuration on Cisco NX-OS devices in the network (including the originating device).

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

Ensure that you have enable user role configuration distribution on all Cisco NX-OS devices that you want to include in the distribution (see the "Distributing the User Role Configuration" section).

SUMMARY STEPS

1. configure terminal

2. show role {pending | pending-diff}

3. role commit

4. exit

5. show role session status

6. copy running-config startup-config

DETAILED STEPS

Discarding the User Role Distribution Session

You can discard the temporary database of user role changes and end the CFS distribution session.

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

You have enabled user role configuration distribution the NX-OS device (see the "Distributing the User Role Configuration" section)

SUMMARY STEPS

1. configure terminal

2. show role {pending | pending-diff}

3. role abort

4. exit

5. show role session status

DETAILED STEPS

Clearing the User Role Distribution Session

You can clear the ongoing Cisco Fabric Services distribution session (if any) and unlock the fabric for the user role feature.

You have enabled user role configuration distribution the NX-OS device (see the "Distributing the User Role Configuration" section)

BEFORE YOU BEGIN

Ensure that you are in the correct VDC (or use the switchto vdc command).

SUMMARY STEPS

1. clear role session

2. show role session status

DETAILED STEPS

Verifying User Accounts and RBAC Configuration

To display user account and RBAC configuration information, perform one of the following tasks:

For detailed information about the fields in the output from these commands, see the Cisco Nexus 7000 Series NX-OS Security Command Reference, Release 4.1.

Example User Accounts and RBAC Configuration

The following example shows how to configure a user role:

role name UserA

  rule 3 permit read feature l2nac

  rule 2 permit read feature dot1x

  rule 1 deny command clear *

The following example shows how to configure a user role feature group:

role feature-group name Security-features

  feature radius

  feature tacacs

  feature dot1x

  feature aaa

  feature l2nac

  feature acl

  feature access-list

Default Settings

Table 7-1 lists the default settings for user accounts and RBAC parameters.

Additional References

For additional information related to implementing RBAC, see the following sections:

•Related Documents

•Standards

•MIBs

Related Documents

Standards

MIBs

Feature History for User Accounts and RBAC

Table 7-2 lists the release history for this feature.