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Oracle Solaris 11.1 Administration: Security Services     Oracle Solaris 11.1 Information Library
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Part I Security Overview

1.  Security Services (Overview)

Part II System, File, and Device Security

2.  Managing Machine Security (Overview)

Controlling Access to a Computer System

Maintaining Physical Security

Maintaining Login Control

Managing Password Information

Password Encryption

Special System Accounts

Remote Logins

Controlling Access to Devices

Device Policy (Overview)

Device Allocation (Overview)

Controlling Access to Machine Resources

Address Space Layout Randomization

Limiting and Monitoring Superuser Access

Configuring Role-Based Access Control to Replace Superuser

Preventing Unintentional Misuse of System Resources

Setting the PATH Variable

Assigning a Restricted Shell to Users

Restricting Access to Data in Files

Restricting setuid Executable Files

Using the Secure by Default Configuration

Using Resource Management Features

Using Oracle Solaris Zones

Monitoring Use of Machine Resources

Monitoring File Integrity

Controlling Access to Files

Protecting Files With Encryption

Using Access Control Lists

Sharing Files Across Machines

Restricting root Access to Shared Files

Controlling Network Access

Network Security Mechanisms

Authentication and Authorization for Remote Access

Firewall Systems

Encryption and Firewall Systems

Reporting Security Problems

3.  Controlling Access to Systems (Tasks)

4.  Virus Scanning Service (Tasks)

5.  Controlling Access to Devices (Tasks)

6.  Verifying File Integrity by Using BART (Tasks)

7.  Controlling Access to Files (Tasks)

Part III Roles, Rights Profiles, and Privileges

8.  Using Roles and Privileges (Overview)

9.  Using Role-Based Access Control (Tasks)

10.  Security Attributes in Oracle Solaris (Reference)

Part IV Cryptographic Services

11.  Cryptographic Framework (Overview)

12.  Cryptographic Framework (Tasks)

13.  Key Management Framework

Part V Authentication Services and Secure Communication

14.  Using Pluggable Authentication Modules

15.  Using Secure Shell

16.  Secure Shell (Reference)

17.  Using Simple Authentication and Security Layer

18.  Network Services Authentication (Tasks)

Part VI Kerberos Service

19.  Introduction to the Kerberos Service

20.  Planning for the Kerberos Service

21.  Configuring the Kerberos Service (Tasks)

22.  Kerberos Error Messages and Troubleshooting

23.  Administering Kerberos Principals and Policies (Tasks)

24.  Using Kerberos Applications (Tasks)

25.  The Kerberos Service (Reference)

Part VII Auditing in Oracle Solaris

26.  Auditing (Overview)

27.  Planning for Auditing

28.  Managing Auditing (Tasks)

29.  Auditing (Reference)



Controlling Access to Machine Resources

Some system resources are protected by default. Additionally, as system administrator, you can control and monitor system activity. You can set limits on who can use what resources. You can log resource use, and you can monitor who is using the resources. You can also set up your systems to minimize improper use of resources.

Address Space Layout Randomization

Oracle Solaris tags many of its userland binaries to enable address space layout randomization (ASLR). ASLR randomizes the starting address of key parts of an address space. This security defense mechanism can cause Return Oriented Programming) (ROP) attacks to fail when they try to exploit software vulnerabilities.

Zones inherit this randomized layout for their processes. Because the use of ASLR might not be optimal for all binaries, the use of ASLR is configurable at the zone level and at the binary level.

Three ASLR configurations are possible:

The sxadm command is used to configure ASLR. You must assume the root role to run this command. For examples and information, see the sxadm(1M) man page. For developer assistance, see Developer’s Guide to Oracle Solaris 11 Security.

Limiting and Monitoring Superuser Access

Your system requires a root password for superuser access. In the default configuration, a user cannot remotely log in to a system as root. When logging in remotely, a user must log in with the user's user name and then use the su command to become root. You can monitor who has been using the su command, especially those users who are trying to gain superuser access. For procedures that monitor superuser and limit access to superuser, see Monitoring and Restricting root Access (Tasks).

Configuring Role-Based Access Control to Replace Superuser

Role-based access control (RBAC), a feature of Oracle Solaris, is designed to distribute the capabilities of superuser to administrative roles. Superuser, the root user, has access to every resource in the system. With RBAC, you can replace many of root's responsibilities with a set of roles with discrete powers. For example, you can set up one role to handle user account creation and another role to handle system file modification. Although you might not modify the root account, you can leave the account as a role, then not assign the role. This strategy effectively removes root access to the system.

Each role requires that a known user log in with her or his user name and password. After logging in, the user then assumes the role with a specific role password. For more information about RBAC, see Role-Based Access Control (Overview).

Preventing Unintentional Misuse of System Resources

You can prevent you and your users from making unintentional errors in the following ways:

Setting the PATH Variable

You should take care to correctly set the PATH variable. Otherwise, you can accidentally run a program that was introduced by someone else. The intruding program can corrupt your data or harm your system. This kind of program, which creates a security hazard, is referred to as a Trojan horse. For example, a substitute su program could be placed in a public directory where you, as system administrator, might run the substitute program. Such a script would look just like the regular su command. Because the script removes itself after execution, you would have little evidence to show that you have actually run a Trojan horse.

The PATH variable is automatically set at login time. The path is set through your initialization files, such as .bashrc and /etc/profile. When you set up the user search path so that the current directory (.) comes last, you are protected from running this type of Trojan horse. The PATH variable for the root account should not include the current directory at all.

Assigning a Restricted Shell to Users

The standard shell allows a user to open files, execute commands, and so on. The restricted shell limits the ability of a user to change directories and to execute commands. The restricted shell is invoked with the /usr/lib/rsh command. Note that the restricted shell is not the remote shell, which is /usr/sbin/rsh.

The restricted shell differs from a standard shell in the following ways:

The restricted shell enables you to limit a user's ability to stray into system files. The shell creates a limited environment for a user who needs to perform specific tasks. The restricted shell is not completely secure, however, and is only intended to keep unskilled users from inadvertently doing damage.

For information about the restricted shell, use the man -s1m rsh command to see the rsh(1M) man page.

Restricting Access to Data in Files

Because Oracle Solaris is a multiuser environment, file system security is the most basic security risk on a system. You can use traditional UNIX file protections to protect your files. You can also use the more secure access control lists (ACLs).

You might want to allow some users to read some files, and give other users permission to change or delete some files. You might have some data that you do not want anyone else to see. Chapter 7, Controlling Access to Files (Tasks) discusses how to set file permissions.

Restricting setuid Executable Files

Executable files can be security risks. A few executable programs still have to be run as root to work properly. These setuid programs run with the user ID set to 0. Anyone who is running these programs runs the programs with the root ID. A program that runs with the root ID creates a potential security problem if the program was not written with security in mind.

Except for the executables that Oracle ships with the setuid bit set to root, you should disallow the use of setuid programs. If you cannot disallow the use of setuid programs, then you must restrict their use. Secure administration requires few setuid programs.

For more information, see Protecting Executable Files From Compromising Security. For procedures, see Protecting Against Programs With Security Risk (Task Map).

Using the Secure by Default Configuration

By default, when Oracle Solaris is installed, a large set of network services are disabled. This configuration is called “Secure by Default” (SBD). With SBD, the only network service that accepts network requests is the sshd daemon. All other network services are disabled or handle local requests only. To enable individual network services, such as ftp, you use the Service Management Facility (SMF) feature of Oracle Solaris. For more information, see the netservices(1M) and smf(5) man pages.

Using Resource Management Features

Oracle Solaris software provides sophisticated resource management features. Using these features, you can allocate, schedule, monitor, and cap resource use by applications in a server consolidation environment. The resource controls framework enables you to set constraints on system resources that are consumed by processes. Such constraints help to prevent denial-of-service attacks by a script that attempts to flood a system's resources.

With these resource management features, you can designate resources for particular projects. You can also dynamically adjust the resources that are available. For more information, see Part I, Oracle Solaris Resource Management, in Oracle Solaris 11.1 Administration: Oracle Solaris Zones, Oracle Solaris 10 Zones, and Resource Management.

Using Oracle Solaris Zones

Oracle Solaris zones provide an application execution environment in which processes are isolated from the rest of the system within a single instance of the Oracle Solaris OS. This isolation prevents processes that are running in one zone from monitoring or affecting processes that are running in other zones. Even a process running with superuser capabilities cannot view or affect activity in other zones.

Oracle Solaris zones are ideal for environments that place several applications on a single server. For more information, see Part II, Oracle Solaris Zones, in Oracle Solaris 11.1 Administration: Oracle Solaris Zones, Oracle Solaris 10 Zones, and Resource Management.

Monitoring Use of Machine Resources

As a system administrator, you need to monitor system activity. You need to be aware of all aspects of your machines, including the following:

With this kind of knowledge, you can use the available tools to audit system use and monitor the activities of individual users. Monitoring is very useful when a breach in security is suspected. For more information about the audit service, see Chapter 26, Auditing (Overview).

Monitoring File Integrity

As a system administrator, you need assurance that the files that were installed on the systems that you administer have not changed in unexpected ways. In large installations, a comparison and reporting tool about the software stack on each of your systems enables you to track your systems. The Basic Audit Reporting Tool (BART) enables you to comprehensively validate systems by performing file-level checks of one or more systems over time. Changes in a BART manifest across systems, or for one system over time, can validate the integrity of your systems. BART provides manifest creation, manifest comparison, and rules for scripting reports. For more information, see Chapter 6, Verifying File Integrity by Using BART (Tasks).