Windows Vista Security GuideChapter 1: Implementing the Security BaselineWindows Vista™ is the most secure operating system that Microsoft has produced to date. However, you may need to make specific configuration changes to meet the network requirements of your environment. The purpose of this chapter is to demonstrate how relatively easy it is to configure security settings to harden client computers running the default operating system that are joined to a domain using the Active Directory® directory service. This chapter provides a simple set of procedures to implement prescribed security settings to enhance the default security of the operating system. The streamlined procedures in this chapter offer a fast and efficient means for you to harden the Windows Vista–based client computers in your environment. You can now harden the default operating system using only Group Policy objects (GPOs). Previous guidance from Microsoft required importing Security Template .inf files and extensive manual modification of the Administrative Templates portion of several GPOs. Working with these files and templates is no longer necessary. However, the Security Template .inf files still accompany this guide so that you can use them to harden stand-alone client computers. All of the recommended Group Policy settings are documented in Appendix A, "Security Group Policy Settings." To deploy this guidance, you need to:
WarningIt is essential to thoroughly test your OU and GPO designs before deploying them in a production environment. The "Implementing the Security Policies" section in this chapter provides procedural details you can use to create and deploy the OU structure and security GPOs during both the test and production phases of the implementation. The baseline GPOs that accompany this guide provide a combination of tested settings that enhance security for client computers running Windows Vista in the following two distinct environments:
This chapter is concerned with the EC environment. For an explanation of the SSLF environment and the process to apply the security settings that are specific to it, see Chapter 5, "Specialized Security – Limited Functionality." On This Page
Enterprise Client EnvironmentThe Enterprise Client (EC) environment referred to in this chapter consists of a domain using Active Directory® directory service in which computers running Microsoft® Windows Server® 2003 R2 or Windows Server 2003 with Service Pack 1 (SP1) and Active Directory manage client computers that can run either Windows Vista or Windows XP®. The client computers are managed in this environment through Group Policy, which is applied to sites, domains, and OUs. Group Policy provides a centralized infrastructure within Active Directory that enables directory-based change and configuration management of user and computer settings, including security and user data. Security Design and ImplementationThe security design that this chapter recommends forms the starting point for the scenarios in this guide, as well as the mitigation suggestions for the scenarios. The following sections in this chapter detail the guide's core security design, and provide procedures to test and implement the design for computers running Windows Vista:
OU Design for Security PoliciesAn OU is a container within a domain that uses Active Directory. An OU may contain users, groups, computers, and other OUs. If an OU contains other OUs, it is a parent OU. An OU within a parent OU is a child OU. You can link a GPO to an OU, which will then apply the GPO's settings to the users and computers that are contained in that OU and its child OUs. And to facilitate administration, you can delegate administrative authority to each OU. OUs provide an easy way to group users and computers to provide an effective way to segment administrative boundaries. Microsoft recommends that organizations assign users and computers to separate OUs, because some settings only apply to users and other settings only apply to computers. You can delegate control over a group or an individual OU by using the Delegation Wizard in the Microsoft Management Console (MMC) Active Directory Users and Computers snap-in tool. See the "More Information" section at the end of this chapter for links to documentation about how to delegate authority. One of the primary goals of an OU design for any environment is to provide a foundation for a seamless Group Policy implementation that applies to all client computers in Active Directory. This ensures that the client computers meet the security standards of your organization. The OU design must also provide an adequate structure to accommodate security settings for specific types of users in an organization. For example, developers may require access to their computers that average users do not. Also, laptop users may have different security requirements than desktop users. The following figure illustrates a simple OU structure that is sufficient for the Group Policy discussion in this chapter. The OU structure may differ from the requirements for your organization's environment.
Figure 1.1 Example OU structure for computers running Windows Vista Department OUBecause security requirements often vary within an organization, it may make sense to create department OUs in your environment. You can use this OU to apply security settings through a GPO to computers and users in their respective department OUs. Windows Vista Users OUThis OU contains the user accounts for the EC environment. The settings that you apply to this OU are described in detail in Appendix A, "Security Group Policy Settings." Windows Vista Computers OUThis OU contains child OUs for each type of client computer running Windows Vista in the EC environment. This guide focuses on security guidance for desktop and laptop computers. For this reason, the engineers for this guide created the following computer OUs:
GPO Design for Security PoliciesA GPO is a collection of Group Policy settings that are essentially the files created by the Group Policy snap-in. The settings are stored at the domain level and affect users and computers contained in sites, domains, and OUs. You can use GPOs to ensure that specific policy settings, user rights, and computer behavior apply to all client computers or users in an OU. Using Group Policy instead of a manual configuration process makes it simple to manage and update changes for many computers and users. Manual configuration is not only inefficient, because it requires a technician to visit each client computer, but it is also potentially ineffective. This is primarily because if the policy settings in domain-based GPOs are different than those applied locally, the domain-based GPO policy settings will overwrite the locally applied policy settings.
Figure 1.2 GPO order of precedence The previous figure shows the order of precedence in which GPOs are applied to a computer that is a member of the Child OU, from the lowest order (1) to the highest order (5). Group Policy is applied first from the local security policy of each client computer running Windows Vista. After the local security policy is applied, GPOs are next applied at the site level, and then at the domain level. For Windows Vista–based client computers that are nested in several OU layers, GPOs are applied in order from the parent OU level in the hierarchy to the lowest child OU level. The final GPO is applied from the OU that contains the client computer. This order of GPO processing for Group Policy—local security policy, site, domain, parent OU, and child OU—is significant because GPOs that are applied later in the process will overwrite those applied earlier. User GPOs are applied in the same manner. The following considerations apply when you design Group Policy:
Recommended GPOsTo implement the OU design described above requires a minimum of four GPOs:
The following figure expands on the preliminary OU structure to show the linkage between these GPOs and the OU design.
Figure 1.3 Example OU structure and GPO links for computers running Windows Vista
In the example in Figure 1.3, laptop computers are members of the Laptop OU. The first policy that is applied is the local security policy on the laptop computers. Because there is only one site in this example, no GPO is applied at the site level, which leaves the Domain GPO as the next policy that is applied. Finally, the Laptop GPO is applied. Note The Desktop Policyis not applied to any laptops because it is not linked to any OUs in the hierarchy that contains the Laptop OU. As a precedence example, consider a scenario in which the policy setting for Allow logon through Terminal Servicesis set to apply to the following OUs and user groups:
In this example, a user whose account is in the Remote Desktop Users group can log on to a laptop through Terminal Services because the Laptop OU is a child of the Windows Vista Computers OU and the child policy takes precedence. If you enable the No Override policy option in the GPO for the Windows Vista Computers OU, only users with accounts in the Administrators group can log on to the laptop computer through Terminal Services. This is because theNo Override option prevents the child OU policy from overwriting the policy applied earlier in the process. Implementing the Security PoliciesImplementing the security design for the two environments described in this guide requires you to use the Group Policy Management Console (GPMC), and GPMC-based scripts. GPMC is integrated into the Windows Vista operating system, so you do not have to download and install the console each time you need to manage GPOs on a different computer. Unlike security guidance for previous Windows operating systems, the prescriptive guidance in this guide for Windows Vista greatly automates the process to test and implement the security design for the EC environment. This guidance has been developed and tested to provide you with the most efficient process possible to reduce overhead associated with the implementation process. Important You must perform all of the procedures in this guide on a client computer running Windows Vista that is joined to a domain using Active Directory. In addition, the user who performs the procedures must have Domain Administrator privileges. If you use the Microsoft Windows® XP or Windows Server® 2003 operating systems, the Windows Vista–specific security settings will not be visible in the GPMC. To implement the security design, there are three key tasks to complete:
This section of the chapter describes these tasks and procedures and the functionality of the GPOAccelerator.wsf script, which automatically creates the prescribed GPOs. The GPOAccelerator.wsf ScriptThe key tool that the Windows Vista Security Guide.msi file installs for you is the GPOAccelerator.wsf script. The main feature of this script is that it automatically creates all the GPOs you need to apply this guidance. You do not need to spend a lot of time manually editing policy settings and applying templates. For the client computers in the EC environment, the script creates the following four GPOs:
Important To successfully implement the security design in this guide for the EC environment, ensure that you thoroughly test the design before deploying it in your production environment. Use the GPOAccelerator.wsf script to:
Test the Design in a Lab EnvironmentThe GPOs provided with this guide have been thoroughly tested. However, it is important to perform your own testing in your own environment. To save time, you can use the GPOAccelerator.wsf script to create the prescribed GPOs and the recommended OU structure, and then automatically link the GPOs to the OUs. Task 1: Create the EC EnvironmentThe GPOAccelerator.wsf script is located in the Windows Vista Security Guide\ Note The GPOAccelerator Tool folder and subfolders for it must be present on the local computer for the script to run as described in the following procedure. To create the GPOs and link them to the appropriate OUs in a lab environment
Task 2: Use the GPMC to Link the VSG EC Domain Policy to the DomainYou are now ready to link the domain GPO to the domain. The following instructions describe how to use the GPMC on a client computer running Windows Vista to link the VSG EC Domain Policy to the domain. To link the VSG EC Domain Policy
Important Ensure that the VSG EC Domain Policy has its Link Order set to1. Failure to do this will cause other GPOs linked to the domain, such as the Default Domain Policy GPO, to overwrite the Windows Vista Security Guide settings. Task 3: Use the GPMC to Check Your ResultsYou can use the GPMC to check the results of the script. The following procedure describes how to use the GPMC on a client computer running Windows Vista to verify the GPOs and OU structure that the GPOAccelerator.wsf script creates for you. To verify the results of the GPOAccelerator.wsf script
All of the GPOs that the GPOAccelerator.wsf script creates are fully populated with the settings that this guide prescribes. You can now use the Active Directory Users and Computers tool to test the design by moving users and computers into their respective OUs. For details about the settings contained in each GPO, see Appendix A, "Security Group Policy Settings." Deploy the Design in a Production EnvironmentTo save time, you can use the GPOAccelerator.wsf script to create the GPOs for the EC environment. Then you can link the GPOs to the appropriate OUs in your existing structure. In larger domains with large numbers of OUs, you will need to consider how to use your existing OU structure to deploy the GPOs. If possible, you should keep computer OUs distinct from user OUs. Laptop and desktop computers also should be organized in their own OUs. If such a structure is not possible in your environment, you may need to modify the GPOs. You can use the settings reference in Appendix A, "Security Group Policy Settings" to help you decide what modifications may be necessary.
Note As discussed in the previous section, you can use the GPOAccelerator.wsf script with Task 1: Create the GPOsYou create the EC GPOs described in this guide using the GPOAccelerator.wsf script. The GPOAccelerator.wsf script is located in the Windows Vista Security Guide\GPOAccelerator Tool folder that the Microsoft Windows Installer (.msi) file creates for you. Note You can also simply copy the GPOAccelerator Tool directory from a computer where the directory is installed to another computer that you want to use to run the script. The GPOAccelerator Tool folder and subfolders for it must be present on the local computer for the script to run as described in the following procedure. To create the GPOs in a production environment
Task 2: Use the GPMC to Check Your ResultsYou can use the GPMC to ensure that the script has successfully created all of the GPOs. The following procedure describes how to use the GPMC on a client computer running Windows Vista to verify the GPOs that the GPOAccelerator.wsf script creates. To verify the results of the GPOAccelerator.wsf script
You can now use GPMC to link each GPO to the appropriate OU. The final task in this process explains how to do this. Task 3: Use the GPMC to Link the GPOs to the OUsThe following procedure describes how to use the GPMC on a client computer running Windows Vista to accomplish this task. To link the GPOs in a production environment
Note You also can drag a GPO from under the Group Policy Objects node to an OU. However, you can only perform this drag-and-drop operation within the same domain. To confirm the GPO linkages using the GPMC
– Or –
Note You can use the GPMC to unlink the GPOs and, optionally, delete them. Then use the GPMC, or the Active Directory Users and Computers console, to delete any OUs that you no longer need. To completely undo all Active Directory modifications made by the GPOAccelerator.wsf script, you must manually delete the EC-VSGAuditPolicy.cmd file, the EC-ApplyAuditPolicy.cmd, and the EC-AuditPolicy.txt file from the NETLOGON share of one of your domain controllers. For additional details on how to completely remove the implementation of the Audit policy, refer to the "Audit Policy" section in Appendix A, "Security Group Policy Settings." All of the GPOs that the GPOAccelerator.wsf script creates are fully populated with the settings that this guide prescribes. You can now use the Active Directory Users and Computers tool to test the design by moving users and computers into their respective OUs. For details about the settings contained in each GPO, see Appendix A, "Security Group Policy Settings." Migrating GPOs to a Different Domain (Optional)If you have modified the GPOs in this solution, or you have created your own GPOs and you want to use them across more than one domain, you will need to migrate the GPOs. Migrating a GPO that works in one domain to another domain requires some planning, but the basic procedure is fairly straightforward. There are two important data aspects of GPOs to consider during the planning process:
More information about GPO migration appears in the GPMC Help. The "Migrating GPOs Across Domains with GPMC" white paper also provides additional information about migrating GPOs between domains. The GPOAccelerator ToolThe tools and templates that accompany this guide include scripts and Security Templates. This section provides background information about these resources. The key tool that runs the core script for this security guidance is GPOAccelerator.wsf, which is located in the Windows Vista Security Guide\GPOAccelerator Tool\Security Group Policy Objects folder. This section also includes information about how to modify the GPMC to view GPO settings, and the subdirectory structure and types of files that accompany this guide. The Windows Vista Security Guide Settings.xls file that also accompanies this guide provides another resource that you can use to compare setting values. GPMC and SCE ExtensionsThe solution presented in this guide uses GPO settings that do not display in the standard user interface (UI) for the GPMC in Windows Vista or the Security Configuration Editor (SCE) tool. These settings, which are all prefixed with MSS:, were developed by the Microsoft Solutions for Security group for previous security guidance. Important The SCE extensions, and the GPOAccelerator.wsf script, are designed for you to run them from a Windows Vista-based computer. These tools will not work correctly if you attempt to run them from a computer using Windows XP or Windows Server 2003. For this reason, you need to extend these tools so that you can view the security settings and edit them as required. To accomplish this, the GPOAccelerator.wsf script automatically updates your computer while it creates the GPOs. If you want to administer the Windows Vista Security Guide GPOs from another computer running Windows Vista, use the following procedure to update the SCE on that computer. To modify the SCE to display MSS settings
Important This script only modifies SCE to display MSS settings; it does not create GPOs or OUs. The following procedure removes the additional MSS security settings, and then resets the SCE tool to the default settings in Windows Vista. To reset the SCE tool to the default settings in Windows Vista
Previous Security SettingsSecurity Templates are provided so that if you want to build your own policies, rather than use or modify the policies supplied with this guide, you can import the relevant security settings. Security Templates are text files that contain security setting values. They are subcomponents of the GPOs. You can modify the policy settings that are contained in the Security Templates in the MMC Group Policy Object Editor snap-in. Unlike previous versions of the Windows operating system, Windows Vista does not come with predefined Security Templates, although you can still use the existing Security Templates as required. Security Templates are included in the Windows Installer (.msi) file that accompanies this guide. The following templates for the EC environment are located in the GPOAccelerator Tool\Security Templates folder:
Important You do not need to use the Security Templates to deploy the solution described in this guide. The templates provide an alternative to the GPMC-based solution, and only cover computer security settings that appear under Computer Configuration\Windows Settings\Security Settings. For example, you cannot manage Internet Explorer or Windows Firewall settings in the GPOs using a Security Template, and user settings are not included. Using Security TemplatesIf you want to use the Security Templates you must first extend the SCE so that the custom MSS security settings display in the UI. See the procedure in the previous "GPMC and SCE Extensions" section in this chapter for details. When you can view the templates, you can use the following procedure to import them into the GPOs that you have created as needed. To import a Security Template into a GPO
You can also use the Security Templates supplied with this guide to modify the local security policy on stand-alone client computers running Windows Vista. The GPOAccelerator.wsf script simplifies the process to apply the templates. To apply the Security Templates to create local Group Policy on a stand-alone client computer running Windows Vista
To restore local Group Policy to the default settings in Windows Vista
Subdirectories and FilesWhen you run the Windows Installer (.msi) file, it creates the Windows Vista Security Guide\GPOAccelerator Tool folder by default in a location on your computer that you specify. The .msi file creates the following subdirectory structure in the GPOAccelerator Tool folder, as well as the files described in the following table. Table 1.1 Subdirectories, Files, and Descriptions
More InformationThe following links provide additional information about Windows Vista security-related topics:
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