Planning for Security in Trusted Extensions

This section outlines the planning that is required before enabling and configuring Trusted Extensions software.

• Understanding Trusted Extensions

• Understanding Your Site's Security Policy

• Devising an Administration Strategy for Trusted Extensions

• Devising a Label Strategy

• Planning System Hardware and Capacity for Trusted Extensions

• Planning Your Trusted Network

• Planning for Zones in Trusted Extensions

• Planning for Multilevel Access

• Planning for the LDAP Naming Service in Trusted Extensions

• Planning for Auditing in Trusted Extensions

• Planning User Security in Trusted Extensions

• Devising a Configuration Strategy for Trusted Extensions

• Collecting Information Before Enabling Trusted Extensions

• Backing Up the System Before Enabling Trusted Extensions

For a checklist of Trusted Extensions configuration tasks, see Appendix B, Configuration Checklist for Trusted Extensions. If you are interested in localizing your site, see For International Customers of Trusted Extensions. If you are interested in running an evaluated configuration, see Understanding Your Site's Security Policy.

Understanding Trusted Extensions

The enabling and configuration of Trusted Extensions involves more than loading executable files, specifying your site's data, and setting configuration variables. Considerable background knowledge is required. Trusted Extensions software provides a labeled environment that is based on two Oracle Solaris features:

• Capabilities that in most UNIX environments are assigned to superuser are handled by discrete administrative roles.

• The ability to override security policy can be assigned to specific users and applications.

In Trusted Extensions, access to data is controlled by special security tags. These tags are called labels. Labels are assigned to users, processes, and objects, such as data files and directories. These labels supply mandatory access control (MAC), in addition to UNIX permissions, or discretionary access control (DAC).

Understanding Your Site's Security Policy

Trusted Extensions effectively enables you to integrate your site's security policy with the Oracle Solaris OS. Thus, you need to have a good understanding of the scope of your policy and how Trusted Extensions software can implement that policy. A well-planned configuration must provide a balance between consistency with your site security policy and convenience for users who are working on the system.

Trusted Extensions is configured by default to conform with the Common Criteria for Information Technology Security Evaluation (ISO/IEC 15408) at Assurance Level EAL4 against the following protection profiles:

• Labeled Security Protection Profile

• Controlled Access Protection Profile

• Role-Based Access Control Protection Profile

To meet these evaluated levels, you must configure LDAP as the naming service. Note that your configuration might no longer conform with the evaluation if you do any of the following:

• Change the kernel switch settings in the /etc/system file.

• Turn off auditing or device allocation.

• Change the default entries in public files in the /usr directory.

For more information, see the Common Criteria web site.

Devising an Administration Strategy for Trusted Extensions

The root role or the System Administrator role is responsible for enabling Trusted Extensions. You can create roles to divide administrative responsibilities among several functional areas:

• The security administrator is responsible for security-related tasks, such as setting up and assigning sensitivity labels, configuring auditing, and setting password policy.

• The system administrator is responsible for the non-security aspects of setup, maintenance, and general administration.

• More limited roles can be configured. For example, an operator could be responsible for backing up files.

As part of your administration strategy, you need to decide the following:

• Which users are handling which administrative responsibilities

• Which non-administrative users are allowed to run trusted applications, meaning which users are permitted to override security policy, when necessary

• Which users have access to which groups of data

Devising a Label Strategy

Planning labels requires setting up a hierarchy of sensitivity levels and a categorization of information on your system. The label_encodings file contains this type of information for your site. You can use one of the label_encodings files that are supplied with Trusted Extensions software. You could also modify one of the supplied files, or create a new label_encodings file that is specific to your site. The file must include the Oracle-specific local extensions, at least the COLOR NAMES section.

Planning labels also involves planning the label configuration. After enabling the Trusted Extensions service, you need to decide if the system can run at a single label only, or if the system can run at multiple labels. If your regular users all operate at the same security label, then you can configure systems that will not be used for administration as single-label systems.

For more information, see Oracle Solaris Trusted Extensions Label Administration. You can also refer to Compartmented Mode Workstation Labeling: Encodings Format.

For International Customers of Trusted Extensions

When localizing a label_encodings file, international customers must localize the label names only. The administrative label names, ADMIN_HIGH and ADMIN_LOW, must not be localized. All labeled hosts that you contact, from any vendor, must have label names that match the label names in the label_encodings file.

Trusted Extensions supports fewer locales than does the Oracle Solaris OS. When you are working in a locale that Trusted Extensions does not support, text that is specific to Trusted Extensions, such as error messages about labels, is not translated into your locale. Oracle Solaris software continues to be translated into your locale.

Planning System Hardware and Capacity for Trusted Extensions

System hardware includes the system itself and its attached devices. Such devices include tape drives, microphones, CD-ROM drives, and disk packs. Hardware capacity includes system memory, network interfaces, and disk space.

• Follow the recommendations for installing an Oracle Solaris release, as described in Chapter 2, Preparing to Install Oracle Solaris 11 Express, in Getting Started With Oracle Solaris 11 Express.

• Trusted Extensions features can add to those recommendations:

  • Memory beyond the suggested minimum is required on the following systems:

    • Systems that run at more than one sensitivity label

    • Systems that are used by users who can assume an administrative role

  • More disk space is required on the following systems:

    • Systems that store files at more than one label

    • Systems whose users can assume an administrative role

Planning Your Trusted Network

For assistance in planning network hardware, see Chapter 1, Planning an IPv4 Addressing Scheme (Tasks), in System Administration Guide: IP Services.

Trusted Extensions software recognizes two host types, labeled and unlabeled. Each host type has a default security template, as shown in Table 1-1.

Table 1-1 Default Host Templates in Trusted Extensions

This table describes the purpose of each host type.

Host Type Template Name Purpose unlabeled admin_low At initial boot, labels the global zone. After initial boot, identifies hosts that send packets that do not include labels. For more information, see unlabeled system. cipso cipso Identifies hosts or networks that send CIPSO packets. CIPSO packets are labeled.

If your network can be reached by other networks, you need to specify accessible domains and hosts. You also need to identify which Trusted Extensions hosts are going to serve as gateways. You need to identify the label accreditation range for these gateways, and the sensitivity label at which data from other hosts can be viewed.

The labeling of hosts, gateways, and networks is explained in Chapter 19, Managing Networks in Trusted Extensions (Tasks). These labeling tasks are performed after initial setup.

Planning for Zones in Trusted Extensions

Trusted Extensions software is added to the Oracle Solaris OS in the global zone. You then configure non-global zones that are labeled. You can create one labeled zone for every unique label, though you do not need to create a zone for every label in your label_encodings file.

Part of zone configuration is configuring the network. By default, labeled zones are configured to communicate with the global zone. Additionally, you can configure the zones on the system to communicate with other zones on the network.

• The X server that runs the desktop display is available only from the global zone. In the Oracle Solaris OS, the loopback interface, lo0, can be used to communicate with the global zone. Therefore, the desktop display is available to non-global zones over lo0.

• By default, non-global zones use the global zone to reach the network. You can configure each non-global zone with a unique default route that does not use the global zone.

Trusted Extensions Zones and Oracle Solaris Zones

Trusted Extensions zones, that is, labeled zones are a brand of Oracle Solaris zones. Labeled zones are primarily used to segregate data. In Trusted Extensions, regular users cannot remotely log in to a labeled zone. The zone console is the only interactive interface to a labeled zone, and only root can gain access to the zone console. For more about zone brands, see the brands(5) man page.

Zone Creation in Trusted Extensions

Zone creation in Trusted Extensions is similar to zone creation in the Oracle Solaris OS. Trusted Extensions provides the txzonemgr script to step you through the process. The script has a command line option to automate the creation of two initial labeled zones.

Planning for Multilevel Access

Typically, printing and NFS are configured as multilevel services. On a properly configured system, every zone must be able to access one or more network addresses if every zone is to access multilevel services. The following configurations provide multilevel services:

• Exclusive IP stack – As in the Oracle Solaris OS, one IP address is assigned for every zone, including the global zone.

  A refinement of this configuration is to assign a separate network information card (NIC) to each zone. Such a configuration is used to physically separate the single-label networks that are associated with each NIC.

• Shared IP stack – One all-zones address is assigned. A refinement of this configuration is to assign some zones an additional, zone-specific address.

A system that meets the following two conditions cannot provide multilevel services:

• One IP address is assigned that the global zone and the labeled zones share.

• No zone-specific addresses are assigned.

Planning for the LDAP Naming Service in Trusted Extensions

If you are not planning to install a network of labeled systems, then you can skip this section.

If you plan to run Trusted Extensions on a network of systems, use LDAP as the naming service. For Trusted Extensions. a populated Sun Java System Directory Server (LDAP server) is required when you configure a network of systems. If your site has an existing LDAP server, you can populate the server with Trusted Extensions databases. To access the server, you set up an LDAP proxy on a Trusted Extensions system.

If your site does not have an existing LDAP server, you then plan to create an LDAP server on a system that is running Trusted Extensions software. The procedures are described in Chapter 5, Configuring LDAP for Trusted Extensions (Tasks).

Planning for Auditing in Trusted Extensions

By default, auditing is enabled when Trusted Extensions is first booted. Therefore, by default, all logins, screenlocks, and logouts are audited. To audit the users who are configuring the system, you can create roles early in the configuration process. When these roles configure the system, the audit records include the login user who assumes the role. See Creating Roles and Users in Trusted Extensions.

Planning auditing in Trusted Extensions is the same as in the Oracle Solaris OS. For details, see Part VII, Oracle Solaris Auditing, in System Administration Guide: Security Services. While Trusted Extensions adds classes, events, and audit tokens, the software does not change how auditing is administered. For Trusted Extensions additions to auditing, see Chapter 24, Trusted Extensions Auditing (Overview).

Planning User Security in Trusted Extensions

Trusted Extensions software provides reasonable security defaults for users. These security defaults are listed in Table 1-2. Where two values are listed, the first value is the default. The security administrator can modify these defaults to reflect the site's security policy. After the security administrator sets the defaults, the system administrator can create all the users, who inherit the established defaults. For descriptions of the keywords and values for these defaults, see the label_encodings(4) and policy.conf(4) man pages.

Table 1-2 Trusted Extensions Security Defaults for User Accounts

The table lists the security defaults in two files, policy.conf and label_encodings.

File name Keyword Value /etc/security/policy.conf IDLECMD lock | logout IDLETIME 30 CRYPT_ALGORITHMS_ALLOW 1,2a,md5,5,6 CRYPT_DEFAULT sha256 LOCK_AFTER_RETRIES no | yes PRIV_DEFAULT basic PRIV_LIMIT all AUTHS_GRANTED solaris.device.cdrw CONSOLE_USER Console User PROFS_GRANTED Basic Solaris User LOCAL DEFINITIONS section of /etc/security/tsol/label_encodings Default User Clearance CNF NEED TO KNOW Default User Sensitivity Label PUBLIC

The system administrator can set up a standard user template that sets appropriate system defaults for every user. For example, by default each user's initial shell is a bash shell. The system administrator can set up a template that gives each user a C shell.

Devising a Configuration Strategy for Trusted Extensions

The following describes the configuration strategy from the most secure strategy to the least secure strategy:

• A two-person team configures the software. The configuration process is audited.

  Two people are at the computer when the software is enabled. Early in the configuration process, this team creates discrete roles, and local users who can assume those roles. The team also sets up auditing to audit events that are executed by roles. After roles are assigned to users, and the computer is rebooted, the users log in and assume a limited role. The software enforces task division by role. The audit trail provides a record of the configuration process. For an illustration of a secure configuration process, see Figure 1-1.

• One person enables and configures the software by assuming the appropriate role. The configuration process is audited.

  Early in the configuration process, the root role creates additional roles. The root role also sets up auditing to audit events that are executed by roles. Once these additional roles have been assigned to the initial user, and the computer is rebooted, the user logs in and assume the appropriate role for the current task. The audit trail provides a record of the configuration process.

• One person enables and configures the software by assuming the root role. The configuration process is not audited.

  By using this strategy, no record is kept of the configuration process.

• The initial setup team changes the root role into a user.

  No record is kept in the software of the name of the user who is acting as root. This setup might be required for remote administration of a headless system.

Task division by role is shown in the following figure. The security administrator configures auditing, protects file systems, sets device policy, determines which programs require privilege to run, and protects users, among other tasks. The system administrator shares and mounts file systems, installs software packages, and creates users, among other tasks.

Figure 1-1 Administering a Trusted Extensions System: Task Division by Role

Collecting Information Before Enabling Trusted Extensions

As when configuring the Oracle Solaris OS, collect system, user, network, and label information before configuring Trusted Extensions. For details, see Collect System Information Before Enabling Trusted Extensions.

Backing Up the System Before Enabling Trusted Extensions

If your system has files that must be saved, perform a backup before enabling the Trusted Extensions service. The safest way to back up files is to do a level 0 dump. If you do not have a backup procedure in place, see the administrator's guide to your current operating system for instructions.