11 SECURING A NETWORK INFRASTRUCTURE Chapter 7

Chapter 7: SECURING A NETWORK INFRASTRUCTURE2 OVERVIEW  List the criteria for selecting operating systems for network servers and workstations.  List the default security settings for the Microsoft Windows Server 2003 and Microsoft Windows XP Professional operating systems.  Describe the problems inherent in keeping the software on a large network installation updated.  Use Microsoft Baseline Security Analyzer (MBSA).  List the criteria for selecting operating systems for network servers and workstations.  List the default security settings for the Microsoft Windows Server 2003 and Microsoft Windows XP Professional operating systems.  Describe the problems inherent in keeping the software on a large network installation updated.  Use Microsoft Baseline Security Analyzer (MBSA).

Chapter 7: SECURING A NETWORK INFRASTRUCTURE3 OVERVIEW (continued)  Use Microsoft Software Update Services (SUS).  Describe the security problems inherent in wireless networking.  List the mechanisms that Windows-based IEEE WLANs can use to authenticate clients and encrypt transmitted data.  Determine the security requirements of your remote access installation.  Control remote access with user account properties.  Create remote access policies.  Use Microsoft Software Update Services (SUS).  Describe the security problems inherent in wireless networking.  List the mechanisms that Windows-based IEEE WLANs can use to authenticate clients and encrypt transmitted data.  Determine the security requirements of your remote access installation.  Control remote access with user account properties.  Create remote access policies.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE4 SELECTING COMPUTERS AND OPERATING SYSTEMS  Purchase and use of computer systems should be governed by policies.  Policies should dictate which operating systems are used for different purposes.  Policies should dictate which hardware is purchased for different purposes.  Purchase and use of computer systems should be governed by policies.  Policies should dictate which operating systems are used for different purposes.  Policies should dictate which hardware is purchased for different purposes.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE5 UNDERSTANDING COMPUTER ROLES  Server Role  Desktop workstation role  Portable workstation role  Server Role  Desktop workstation role  Portable workstation role

Chapter 7: SECURING A NETWORK INFRASTRUCTURE6 UNDERSTANDING THE SERVER ROLE  Servers can perform a number of different roles.  Each role places different demands on the underlying hardware and operating system software.  Some roles require additional hardware: a server that is used for backups requires a connection to a tape drive or some other storage device.  Server systems often include fault-tolerant measures.  Servers can perform a number of different roles.  Each role places different demands on the underlying hardware and operating system software.  Some roles require additional hardware: a server that is used for backups requires a connection to a tape drive or some other storage device.  Server systems often include fault-tolerant measures.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE7 UNDERSTANDING THE DESKTOP WORKSTATION’S ROLE  Workstation hardware is generally less powerful than server hardware.  Workstation hardware typically does not include fault-tolerant measures.  Some applications, such as computer-aided design (CAD), video and sound editing, and geographic mapping, require very high-performance hardware.  Workstation hardware is generally less powerful than server hardware.  Workstation hardware typically does not include fault-tolerant measures.  Some applications, such as computer-aided design (CAD), video and sound editing, and geographic mapping, require very high-performance hardware.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE8 UNDERSTANDING THE PORTABLE WORKSTATION’S ROLE  Portable workstations can include laptops, notebooks, PDAs, and tablet PCs.  Portable workstations have different hardware and configuration requirements from desktop workstations.  Some users may have a desktop workstation and one or more portable workstations.  Portable workstations create additional security concerns since they can be moved both within and outside of the physical security perimeter.  Portable workstations can include laptops, notebooks, PDAs, and tablet PCs.  Portable workstations have different hardware and configuration requirements from desktop workstations.  Some users may have a desktop workstation and one or more portable workstations.  Portable workstations create additional security concerns since they can be moved both within and outside of the physical security perimeter.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE9 CREATING HARDWARE SPECIFICATIONS  Server hardware specifications  Desktop hardware specifications  Portable hardware specifications  Server hardware specifications  Desktop hardware specifications  Portable hardware specifications

Chapter 7: SECURING A NETWORK INFRASTRUCTURE10 SERVER HARDWARE SPECIFICATIONS  Create a hardware specification based on the applications that the server will host.  Use company information such as expected increases in personnel or customer activity when creating the specification.  Factor a reasonable growth margin into the specification.  Consider the ease of future upgrades to preserve investment.  Create a hardware specification based on the applications that the server will host.  Use company information such as expected increases in personnel or customer activity when creating the specification.  Factor a reasonable growth margin into the specification.  Consider the ease of future upgrades to preserve investment.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE11 DESKTOP HARDWARE SPECIFICATIONS  Specify a base hardware configuration that supports most users.  Create additional specifications as needed to accommodate special requirements.  Where possible, use a small number of standard configurations.  Standardized hardware provides many advantages in terms of support.  Specify a base hardware configuration that supports most users.  Create additional specifications as needed to accommodate special requirements.  Where possible, use a small number of standard configurations.  Standardized hardware provides many advantages in terms of support.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE12 PORTABLE HARDWARE SPECIFICATIONS  Different types of portable hardware have different hardware requirements.  Many portable computing devices use proprietary technologies.  As with desktop workstations, keep the number of standard configurations to a minimum.  Different types of portable hardware have different hardware requirements.  Many portable computing devices use proprietary technologies.  As with desktop workstations, keep the number of standard configurations to a minimum.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE13 SELECTING OPERATING SYSTEMS When selecting operating systems, you must consider the following:  Application compatibility The operating system you select must support the application software needed by the organization.  Support issues Familiarity with operating systems decreases training costs and improves technical support service.  Security features In highly secure environments, operating systems with advanced security features should be chosen.  Cost Operating system software represents a significant investment, and the availability of funds for software purchases must be considered. When selecting operating systems, you must consider the following:  Application compatibility The operating system you select must support the application software needed by the organization.  Support issues Familiarity with operating systems decreases training costs and improves technical support service.  Security features In highly secure environments, operating systems with advanced security features should be chosen.  Cost Operating system software represents a significant investment, and the availability of funds for software purchases must be considered.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE14 CHOOSING WORKSTATION OPERATING SYSTEMS

Chapter 7: SECURING A NETWORK INFRASTRUCTURE15 CHOOSING SERVER OPERATING SYSTEMS

Chapter 7: SECURING A NETWORK INFRASTRUCTURE16 IDENTIFYING CLIENT AND SERVER DEFAULT SECURITY SETTINGS  Operating systems install with a default set of security settings.  These settings should be evaluated to determine whether they satisfy security requirements.  Windows Server 2003 is designed to be more secure in a default installation than are previous versions of Windows.  Operating systems install with a default set of security settings.  These settings should be evaluated to determine whether they satisfy security requirements.  Windows Server 2003 is designed to be more secure in a default installation than are previous versions of Windows.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE17 EVALUATING SECURITY SETTINGS  File System permissions  Share permissions  Registry permissions  Active Directory permissions  Account Policy settings  Audit policies  File System permissions  Share permissions  Registry permissions  Active Directory permissions  Account Policy settings  Audit policies

Chapter 7: SECURING A NETWORK INFRASTRUCTURE18 FILE SYSTEM PERMISSIONS file or folder’s ownership, permissions, and file system attributes N N T T F F S S F F o o l l d d e e r r P P e e r r m m i i s s s s i i o o n n E E n n a a b b l l e e s s t t h h e e U U s s e e r r o o r r G G r r o o u u p p T T o o Full ControlChange file/folder permissions, take ownership of files/folders, and delete subfolders and files, plus perform the actions permitted by all of the other NTFS permissions. ModifyModify or delete a file/folder, plus perform all actions permitted by the Write permission and the Read & Execute permission. Read & ExecuteRun applications; browse through folders to reach other files and folders, even if the user does not have permission to access those files/folders; and perform all actions permitted by the Read permission and the List Folder Contents permission. List Folder ContentsSee the names of files and subfolders in a folder. ReadRead a file; see the files and subfolders in a folder; and view a (such as Read-only, Hidden, Archive, and System). WriteOverwrite a file, create new files and subfolders within a folder, change a file or folder’s attributes, and view the file or folder’s ownership and permissions.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE19 SHARE PERMISSIONS

Chapter 7: SECURING A NETWORK INFRASTRUCTURE20 REGISTRY PERMISSIONS

Chapter 7: SECURING A NETWORK INFRASTRUCTURE21 ACTIVE DIRECTORY PERMISSIONS  Active Directory has over 25 standard permissions and 67 special permissions.  The following default permission assignments are made to cover most requirements:  Enterprise Admins Receives the Full Control permission for the entire forest  Domain Admins and Administrators Receives a selection of permissions that enables him or her to perform Active Directory object maintenance tasks within their domain  Authenticated Users Receives the Read permission for the entire domain, plus a small selection of very specific Modify permissions  Active Directory has over 25 standard permissions and 67 special permissions.  The following default permission assignments are made to cover most requirements:  Enterprise Admins Receives the Full Control permission for the entire forest  Domain Admins and Administrators Receives a selection of permissions that enables him or her to perform Active Directory object maintenance tasks within their domain  Authenticated Users Receives the Read permission for the entire domain, plus a small selection of very specific Modify permissions

Chapter 7: SECURING A NETWORK INFRASTRUCTURE22 ACCOUNT POLICY SETTINGS

Chapter 7: SECURING A NETWORK INFRASTRUCTURE23 AUDIT POLICIES

Chapter 7: SECURING A NETWORK INFRASTRUCTURE24 PLANNING A SECURITY UPDATE INFRASTRUCTURE  Understanding software update practices  Using Windows Update  Updating a network  Understanding software update practices  Using Windows Update  Updating a network

Chapter 7: SECURING A NETWORK INFRASTRUCTURE25 UNDERSTANDING SOFTWARE UPDATE PRACTICES  Microsoft distributes software updates in two forms:  Service pack A collection of patches and updates that have been tested as a single unit  Hotfix A small patch designed to address a specific issue  Microsoft recommends that service packs are installed on all applicable systems. Hotfixes should only be applied to systems that are experiencing a specific problem.  Microsoft distributes software updates in two forms:  Service pack A collection of patches and updates that have been tested as a single unit  Hotfix A small patch designed to address a specific issue  Microsoft recommends that service packs are installed on all applicable systems. Hotfixes should only be applied to systems that are experiencing a specific problem.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE26 USING WINDOWS UPDATE

Chapter 7: SECURING A NETWORK INFRASTRUCTURE27 UPDATING A NETWORK  Updating PCs on a network presents many challenges to the administrator.  A network security update infrastructure is a series of policies that are designed to help the administrator manage software and security updates on the network.  The security update infrastructure should specify procedures for the identification, testing, and deployment of software updates.  Updating PCs on a network presents many challenges to the administrator.  A network security update infrastructure is a series of policies that are designed to help the administrator manage software and security updates on the network.  The security update infrastructure should specify procedures for the identification, testing, and deployment of software updates.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE28 USING MBSA

Chapter 7: SECURING A NETWORK INFRASTRUCTURE29 TESTING SECURITY UPDATES  All updates, including those related to security, should be tested before they are implemented.  If possible, use a test system with a configuration similar to that of the system on which the update will be applied.  If a test system is not available, updates should be deployed progressively, and systems with the updates should be closely monitored.  All updates, including those related to security, should be tested before they are implemented.  If possible, use a test system with a configuration similar to that of the system on which the update will be applied.  If a test system is not available, updates should be deployed progressively, and systems with the updates should be closely monitored.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE30 USING MICROSOFT SOFTWARE UPDATE SERVICES

Chapter 7: SECURING A NETWORK INFRASTRUCTURE31 SECURING A WIRELESS NETWORK  Wireless networks are becoming increasingly popular as related hardware becomes more affordable, and companies begin to realize the flexibility that wireless networks offer.  Wireless networks present more and different security challenges than their wired counterparts.  Wireless networks are becoming increasingly popular as related hardware becomes more affordable, and companies begin to realize the flexibility that wireless networks offer.  Wireless networks present more and different security challenges than their wired counterparts.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE32 UNDERSTANDING WIRELESS NETWORKING STANDARDS  Wireless networking standards are developed and ratified by the Institute of Electrical and Electronics Engineers (IEEE).  Three standard have been defined:  b The current standard. Offers speeds up to 11 Mbps.  a In development. Uses different frequency ranges than b. Offers speeds up to 54 Mbps.  g Uses the same frequency ranges as b. Offers speeds up to 54 Mbps.  Wireless networking standards are developed and ratified by the Institute of Electrical and Electronics Engineers (IEEE).  Three standard have been defined:  b The current standard. Offers speeds up to 11 Mbps.  a In development. Uses different frequency ranges than b. Offers speeds up to 54 Mbps.  g Uses the same frequency ranges as b. Offers speeds up to 54 Mbps.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE33 WIRELESS NETWORKING TOPOLOGIES

Chapter 7: SECURING A NETWORK INFRASTRUCTURE34 UNDERSTANDING WIRELESS NETWORK SECURITY  Wireless networking presents security risks that are not present when using traditional wired networks.  Logical security becomes of paramount concern, as physical security measures are not necessarily preventative.  Two main concerns when using wireless networks are unauthorized access and data interception.  Wireless networking presents security risks that are not present when using traditional wired networks.  Logical security becomes of paramount concern, as physical security measures are not necessarily preventative.  Two main concerns when using wireless networks are unauthorized access and data interception.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE35 CONTROLLING WIRELESS ACCESS USING GROUP POLICIES

Chapter 7: SECURING A NETWORK INFRASTRUCTURE36 AUTHENTICATING USERS  Open system authentication  Shared key authentication  IEEE 802.1x authentication  Open system authentication  Shared key authentication  IEEE 802.1x authentication

Chapter 7: SECURING A NETWORK INFRASTRUCTURE37 OPEN SYSTEM AUTHENTICATION  The default authentication method used by IEEE devices.  Despite the name, it offers no actual authentication.  A device configured to use Open System authentication will not refuse authentication to another device.  The default authentication method used by IEEE devices.  Despite the name, it offers no actual authentication.  A device configured to use Open System authentication will not refuse authentication to another device.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE38 SHARED KEY AUTHENTICATION  Devices authenticate each other using a secret key that both possess.  The key is shared before authentication using a secure channel.  All the computers in the same BSS must possess the same key.  Devices authenticate each other using a secret key that both possess.  The key is shared before authentication using a secure channel.  All the computers in the same BSS must possess the same key.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE39 IEEE 802.1X AUTHENTICATION  The IEEE 802.1x standard defines a method of authenticating and authorizing users on any 802 LAN.  Most IEEE 802.1x implementations use Remote Authentication Dial-In User Service (RADIUS) servers.  RADIUS typically uses one of the following two authentication protocols:  Extensible Authentication Protocol-Transport Level Security (EAP-TLS)  Protected EAP-Microsoft Challenge Handshake Authentication Protocol version 2 (PEAP-MS-CHAP v2)  The IEEE 802.1x standard defines a method of authenticating and authorizing users on any 802 LAN.  Most IEEE 802.1x implementations use Remote Authentication Dial-In User Service (RADIUS) servers.  RADIUS typically uses one of the following two authentication protocols:  Extensible Authentication Protocol-Transport Level Security (EAP-TLS)  Protected EAP-Microsoft Challenge Handshake Authentication Protocol version 2 (PEAP-MS-CHAP v2)

Chapter 7: SECURING A NETWORK INFRASTRUCTURE40 ENCRYPTING WIRELESS TRAFFIC  The IEEE standard uses an encryption mechanism called Wired Equivalent Privacy (WEP) to secure data while in transit.  WEP uses the RC4 cryptographic algorithm developed by RSA Security, Inc.  WEP allows the key length, as well as the frequency with which the systems generate new keys, to be configured.  The IEEE standard uses an encryption mechanism called Wired Equivalent Privacy (WEP) to secure data while in transit.  WEP uses the RC4 cryptographic algorithm developed by RSA Security, Inc.  WEP allows the key length, as well as the frequency with which the systems generate new keys, to be configured.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE41 SECURING REMOTE ACCESS  Determining security requirements  Controlling access using dial-in properties  Planning authentication  Using remote access policies  Determining security requirements  Controlling access using dial-in properties  Planning authentication  Using remote access policies

Chapter 7: SECURING A NETWORK INFRASTRUCTURE42 DETERMINING SECURITY REQUIREMENTS  Which users require remote access?  Do users require different levels of remote access?  Do users need access to the entire network?  What applications must users run?  Which users require remote access?  Do users require different levels of remote access?  Do users need access to the entire network?  What applications must users run?

Chapter 7: SECURING A NETWORK INFRASTRUCTURE43 CONTROLLING ACCESS USING DIAL-IN PROPERTIES

Chapter 7: SECURING A NETWORK INFRASTRUCTURE44 PLANNING AUTHENTICATION

Chapter 7: SECURING A NETWORK INFRASTRUCTURE45 USING RADIUS  Windows Server 2003 with IAS can be a RADIUS server or a RADIUS proxy.  When configured as a RADIUS server, the computer receiving the authentication request will process and authorize the connection request.  When configured as a RADIUS proxy, the authenti- cation request is forwarded to the configured RADIUS server.  Windows Server 2003 with IAS can be a RADIUS server or a RADIUS proxy.  When configured as a RADIUS server, the computer receiving the authentication request will process and authorize the connection request.  When configured as a RADIUS proxy, the authenti- cation request is forwarded to the configured RADIUS server.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE46 SELECTING AN AUTHENTICATION PROTOCOL

Chapter 7: SECURING A NETWORK INFRASTRUCTURE47 USING REMOTE ACCESS POLICIES  Sets of conditions that users must meet before RRAS authorizes them to access the server or the network  Can be configured to limit user access based on group memberships, day and time restrictions, and many other criteria  Can specify what authentication protocol, and what type of encryption clients must use  Policies can be created based on type of connection, such as dial-up, VPN, or wireless  Sets of conditions that users must meet before RRAS authorizes them to access the server or the network  Can be configured to limit user access based on group memberships, day and time restrictions, and many other criteria  Can specify what authentication protocol, and what type of encryption clients must use  Policies can be created based on type of connection, such as dial-up, VPN, or wireless

Chapter 7: SECURING A NETWORK INFRASTRUCTURE48 REMOTE ACCESS POLICY COMPONENTS  Conditions  Specific attributes that the policy uses to grant or deny authorization to a user. If more than one condition is defined, the user must meet all the conditions before the server can grant access.  Remote access permission  Defines whether the user is allowed to connect to the system through a remote access connection.  Remote access profile  A set of attributes applied to a client once it has been authenticated and authorized.  Conditions  Specific attributes that the policy uses to grant or deny authorization to a user. If more than one condition is defined, the user must meet all the conditions before the server can grant access.  Remote access permission  Defines whether the user is allowed to connect to the system through a remote access connection.  Remote access profile  A set of attributes applied to a client once it has been authenticated and authorized.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE49 CREATING REMOTE ACCESS POLICIES

Chapter 7: SECURING A NETWORK INFRASTRUCTURE50 CHAPTER SUMMARY  When selecting operating systems for servers, you can choose the platform best suited to the server’s role. When selecting workstation operating systems, standardization takes precedence over specialization.  When you install Windows Server 2003 or Windows XP Professional, the operating system Setup program configures a number of security settings with default values that you can either keep or modify.  Microsoft releases updates for its operating systems and applications. Major updates are called service packs. Individual updates are called hotfixes.  MBSA is a tool that scans computers on a network and examines them for security vulnerabilities.  When selecting operating systems for servers, you can choose the platform best suited to the server’s role. When selecting workstation operating systems, standardization takes precedence over specialization.  When you install Windows Server 2003 or Windows XP Professional, the operating system Setup program configures a number of security settings with default values that you can either keep or modify.  Microsoft releases updates for its operating systems and applications. Major updates are called service packs. Individual updates are called hotfixes.  MBSA is a tool that scans computers on a network and examines them for security vulnerabilities.

Chapter 7: SECURING A NETWORK INFRASTRUCTURE51 CHAPTER SUMMARY (continued)  SUS is a tool that streamlines the approval and implementation of software updates.  Most wireless LANs today are based on the standards published by the IEEE. WLANs present additional security risks over wired networks.  To secure a wireless network, you must authenticate the clients before they are granted network access, and encrypt all packets transmitted over the wireless link.  To determine the security requirements you need for your remote access server, determine which users need access and what type of access they need.  Remote access policies are sets of conditions that must be met by remote clients attempting to connect to the Routing and Remote Access server.  SUS is a tool that streamlines the approval and implementation of software updates.  Most wireless LANs today are based on the standards published by the IEEE. WLANs present additional security risks over wired networks.  To secure a wireless network, you must authenticate the clients before they are granted network access, and encrypt all packets transmitted over the wireless link.  To determine the security requirements you need for your remote access server, determine which users need access and what type of access they need.  Remote access policies are sets of conditions that must be met by remote clients attempting to connect to the Routing and Remote Access server.