Planning a Public Key Infrastructure

Planning a Certification Authority Hierarchy Managing Certification Authorities Using Certificates for Authentication

Planning a Certification Authority Hierarchy

Public Key Infrastructure (PKI) Deployment Steps

Reviewing PKI components Determining whether to use a private or public

Certification Authority (CA) Determining the CA structure Planning the scope of a CA Planning offline CAs Designing the Certification Authority hierarchy Planning disaster recovery of CAs

PKI Deployment Steps

Determine whether a public CA or a private CA meets the business needs.

Design a CA hierarchy that allows clients to recognize and verify all issued certificates.

Determine whether to deploy an Enterprise or Standalone scope for private CAs.

Plan security for the root CA. Develop a disaster recovery plan for the

potential failure of a CA.

Reviewing PKI Components

Public Key-Enabled Applications and Services

Choosing a Public CA

Choosing a Private CA

Making the Decision:Implementing Public and Private CAs

Use a public CA when An application requires verification from a trusted

third party The resources necessary to deploy an internal PKI

are not available Time is limited A project requires certificate interoperability

between organizations An application requires liability protection

Making the Decision: Implementing Public and Private CAs (Cont.)

Use a private CA when The organization needs to maintain management

control of all client-associated certificates The certificates will be used only for internal

projects, applications, and services The costs associated with issuing certificates must

be minimized An organization has the expertise to manage and

maintain Certificate Services

Applying the Decision: Implementing Public and Private CAs for Blue Yonder Airlines Public CAs

The online booking Web server must have a public CA-issued certificate.

Ensures customer confidence in the security of sensitive data.

Configure the Web server to require 128-bit encryption.

Private CAs Make it possible to issue smart cards to customers while

maintaining the ability to revoke certificates quickly Provide internal employees with smart card logon and

Extensible Authentication Protocol (EAP) authentication for remote access

A Rooted CA Hierarchy

A Cross-Certification CA Hierarchy

Making the Decision: Designing Certificate Hierarchies

Provide maximum security for the root CA. Limit trusted CAs to an organization’s CAs. Provide interoperability between organizations. Limit which CAs will be trusted from a partner

organization.

Applying the Decision: Designing Certificate Hierarchies for Blue Yonder Airlines Blue Yonder Airlines requires only a rooted CA

hierarchy for the internal network and for Web site customers.

This allows for increased security by removing the root CA from the network.

Blue Yonder Airlines will acquire a certificate for their Web server from a public CA such as Entrust.

There is no business reason to create cross-certification between the company’s CA hierarchy and the Entrust CA hierarchy.

The Entrust certificate will be trusted. The root certificate from Entrust CA will be included in

the Trusted Root Certification Authorities container by default.

Planning the Scope of a CA

Enterprise CA Considerations

Certificate templates Integration with Microsoft Windows 2000

security Storage of data in Active Directory Applications and services that require an

Enterprise CA Reduction in management for certificate

issuance

Deploying a Standalone CA

Standalone CAs can be members of a domain or standalone servers in a workgroup.

All data is stored in a local database. Standalone CAs do not use certificate

templates.

Considerations for Deploying a Standalone CA

If an offline root CA is established If integration of Windows 2000 Certificate

Services with an Exchange 5.5 Key Management Server (KMS) is desirable

If the CA is required to run in the Demilitarized Zone (DMZ)

Making the Decision: Implementing Enterprise CAs

Deploy Certificate Services for an internal deployment where the users will be providing their network credentials for authentication.

Deploy Windows 2000 services that require certificate templates provided only by Enterprise CAs.

Leverage the standard Windows 2000 security model to determine who can acquire specific certificate templates.

Making the Decision: Implementing Standalone CAs

Deploy offline CAs that must operate without communicating with the rest of the network.

Configure the Exchange 5.5 KMS to use x.509 v3 certificates rather than the default x.509 v1 certificates.

Place the CA in a location where it cannot connect to Active Directory.

Applying the Decision: Deploying Enterprise CAs or Standalone CAs at Blue Yonder Airlines Blue Yonder Airlines requires the issuance of

smart cards for both customers and internal user accounts.

Requires deployment of an Enterprise CA. Only an Enterprise CA supports certificates for smart

cards Each CA hierarchy should have an offline root

CA to increase the security of the CA hierarchy.

Requires configuration of a Standalone scope for the CA.

Offline CA Considerations

Storage location of the offline CA Use of a strong Cryptographic Service Provider

(CSP) Publication of the Certificate Revocation List

(CRL) Publication of the Authority Information Access

(AIA) Definition of certificate renewal period

Configuring an Offline Root CA

The primary configuration is performed in the Capolicy.inf file.

Place the Capolicy.inf file in the Systemroot folder before installing Windows 2000 Certificate Services.

Capolicy.inf Configuration File

Capolicy.inf File for Nonroot CAs

Only use a Capolicy.inf configuration file for a nonroot CA to define a Certificate Practice Statement (CPS) for an issuing CA.

The Capolicy.inf text file is the only way to enter information into a CPS for Windows 2000 Certificate Services.

A nonroot CA processes only the [CAPolicy] and [PolicyName] sections of the Capolicy.inf configuration file.

All other sections are ignored.

Configuring the CDPs

Configure Certification Distribution Points (CDPs) for the CRL and Authority Information Access (AIA) associated with the CA.

Configure CDPs in the properties of the Certification Authority.

Define the X.509 extensions for the CA's policy module.

The URLs defined for the CRL and AIA distribution points are included in the properties of any newly issued certificate by the CA.

Making the Decision: Securing Offline Root CAs

Allow the CA to be removed from the network for long periods of time.

Provide the strongest form of encryption at the offline root CA.

Make the CRL and AIA available to network users.

Define a CPS. Provide the most security for your CA

hierarchy.

Applying the Decision: Securing Offline Root CAs for Blue Yonder Airlines

A Standalone CA must be used for the offline root CA.

A second layer of subordinate CAs can also be removed.

A Capolicy.inf configuration file must be configured to issue a CPS that defines usage policy for all customers with airline smart cards.

Attributes for the CA must be set before removing the CA from the network.

CRL publication interval CRL and AIA distribution points The default lifetime for issued certificates

Certification Authority Hierarchy: Structure Based on Usage

Certification Authority Hierarchy:Structure Based on Administration

Certification Authority Hierarchy: Structure Based on Location

Required CA Levels

Create a CA hierarchy that is three to four levels deep.

Hierarchies with fewer than three levels are more vulnerable.

With two levels, if the root level is compromised, all certificates are also compromised.

Hierarchies with more than four levels introduce unnecessary complexity.

Making the Decision:Choosing CA Hierarchy Structures

Usage structure Administrative structure Location structure

Applying the Decision: Implementing CA Hierarchy Structures for Blue Yonder Airlines

Preventing CA Failure

Implement hardware solutions for fault tolerance.

Back up the Certificate Services data regularly. Back up an offline CA server with disk imaging

software.

Making the Decision: Disaster Recovery Plan for CAs

Prevent loss of data in the Certificate Services database.

Ensure that a rebuilt CA is still valid for all issued certificates.

Allow a CA to be recovered. Ensure recoverability.

Applying the Decision: Disaster Recovery Plan for CAs at Blue Yonder Airlines

Include a backup and restore strategy for all CAs.

Schedule regular backups that include the system state backups.

Export the existing private and public keys associated with the CA’s certificate to files and include those files in the regular backup set.

Create an image of the root CA for the hierarchy on a CD.

Managing Certification Authorities

Planning certificate issuance Planning certificate revocation Planning certificate renewal

Planning Certificate Issuance

Certificates must be issued to the necessary users, computers, and network devices.

Issuing certificates involves either Configuring permissions to establish which security

principals have Enroll permissions for specific templates

Appointing a certificate administrator who will review each certificate request and issue or deny the request

Designing Automatic Issuance

Define which certificate templates will be requested by computer accounts within the site, domain, or OU where the Group Policy object is defined.

Assign the correct permissions to the required computers to acquire the certificate templates.

Configure at least one Enterprise CA in the forest to issue the required certificate templates.

Designing Manual Issuance

All user certificates and some computer certificates must be requested manually from a CA.

User certificates cannot automatically be assigned.

Set permissions for each certificate template. Designate a CA to issue the required

certificate templates.

Making the Decision: Planning Certificate Issuance

Restrict access to specific templates. Restrict which CA issues a specific certificate

template. Automate the deployment of computer

certificates. Issue certificates to users. Require a certificate administrator to approve

or reject each certificate request.

Applying the Decision: Planning Certificate Issuance for Blue Yonder Airlines

Computer certificates Require IPSec-specific certificates or multipurpose

Computer certificates for IPSec authentication Configure the Default Domain Policy to issue both

IPSec and Computer certificates User certificates

Cannot automatically issue certificates to internal users

Jenny Sax will make all certificate requests for external customers

Planning Certificate Revocation

Reasons for revoking a certificate before its expiration date

Verifying a revoked certificate When frequent certificate revocations occur The CRL's availability

Making the Decision: Planning CRL Availability for CAs

Create a central location for offline CA CRLs. Determine the optimal publication schedule for

the CRL associated with a CA. Ensure availability of the CRL. Ensure that CRL's are available to external

clients if they receive certificates from the internal network.

Ensure that all CRL's in the CA chain are available.

Applying the Decision: Planning CRL Availability for CAs at Blue Yonder Airlines

Planning Certificate Renewal

Registry values define the lifetime for all issued certificates

Renewing User certificates or Computer certificates

Renewing the CA certificate using the Certification Authority console

Setting the lifetime for CA and SubCA certificates

Making the Decision: Designing a Renewal Policy for Certificates

Define certificate lifetimes based on renewal requirements.

Define a process that users and computers will use to renew their certificates.

Ensure that the CA certificate's remaining lifetime is never shorter than the lifetime for issued certificates.

Plan for renewal dates far in the future.

Applying the Decision: Designing a Renewal Policy for Certificates at Blue Yonder Airlines Install the root CA with the longest lifetime. Renew the root CA's certificate before the

SubCAs expire. The Smartcards CA requires the shortest

validity period. Develop a plan for renewing the internal

network certificates.

Using Certificates for Authentication

Planning smart card logon Planning certificate-based Web authentication

Smart Card Logon Process

Planning Smart Card Deployment

Define which users can enroll for the required types of certificates.

Define a CA to issue the required certificates. Configure a computer and user account to

function as the smart card enrollment station and smart card enrollment agent.

Define the physical process for smart card enrollment.

Defining Permissions for Certificate Templates

Smart card logon requires several certificate templates.

Use SmartcardUser for e-mail purposes. Use SmartcardLogon for network authentication.

Define security so that only the security groups have the permission to enroll for the required certificate.

Permissions are defined in Active Directory Sites And Services by exposing the Services node.

Find the certificate templates in Active Directory Sites And Services\Services\Public Key Services\Certificate Templates.

Required Certificates

EnrollmentAgent MachineEnrollmentAgent SmartcardUser SmartcardLogon

Configuring CAs to Issue the Required Certificates

By default, CAs do not issue any of the required certificate templates for smart card logon.

Only Enterprise CAs can issue certificate templates.

Select an Enterprise CA that is located near the smart card enrollment station.

Acquiring the Required Certificates

The enrollment agent must acquire an EnrollmentAgent certificate.

The smart card enrollment station computer requires a MachineEnrollmentAgent certificate.

Defining the Enrollment Process

Security can be built into the smart card certificate distribution process.

Mandate that the user must be face-to-face with the enrollment agent to obtain a smart card.

Ensure that only the smart card's user knows the associated PIN.

Making the Decision: Smart Card Deployment

Ensure that only authorized personnel can request certificates required for smart card authentication.

Restrict the smart card enrollment process to specific workstations.

Require smart card users to log on with smart cards.

Ensure that only authorized users obtain a smart card.

Define what happens when a smart card is removed from the smart card reader.

Applying the Decision: Smart Card Deployment at Blue Yonder Airlines

External requests Face-to-face interviews will not be possible. Customers must request the cards by filling out an

extensive form. Jenny Sax will determine whether to issue a smart

card to the customer. Safeguard the card if it is issued by sending the card,

the smart card reader, and the PIN in separate packages.

Internal requests Jenny Sax can require face-to-face interviews. Safeguard the process by requiring a form of photo

ID to prove identity.

Certificate Mapping Overview

A Web site can be configured to require certificates for user authentication.

Only the certificate is transmitted to the Web server.

Certificate mapping allows certificates with similar properties to be mapped to a single user account.

Designing Certificate Mapping

Determine where to perform the mapping. Determine the type of mapping to implement. Ensure that all certificates are issued from

trusted root CA hierarchies.

Configuring Authentication

The Web site's authentication configuration can be changed to allow only certificate-based authentication.

Configure the supported authentication methods to prevent Internet Information Server (IIS) from presenting the user with an Authentication dialog box if certificate-based authentication fails.

Only certificates can be used to authenticate users.

Making the Decision: Implementing Account Mapping

Mapping certificates to user accounts One-to-one mapping strategy Many-to-one mapping strategy

Making the Decision: Implementing Account Mapping (Cont.)

Planning where to configure account mapping Active Directory mapping IIS mapping

Applying the Decision: Implementing Account Mapping at Blue Yonder Airlines

Blue Yonder Airlines requires one-to-one mappings.

The easiest place to perform the mapping is in Active Directory.

The certificates are mapped only to a single smart card.

Chapter Summary

PKI deployment steps Reviewing PKI components Determining whether to use a private or public

CA Determining the Certification Authority

structure Planning the scope of a CA Planning offline CAs Designing the Certification Authority hierarchy Planning disaster recovery of CAs

Chapter Summary (Cont.)

Planning certificate issuance Planning certificate revocation Planning certificate renewal Planning smart card logon Planning certificate-based Web authentication