Maximizing Certificate Services Implementations

Creating a Public Key Infrastructure (PKI) environment takes quite a bit of time and planning to build and effort to maintain. Administrators often have to plan well beyond the current levels of hardware and software available to them at the time of implementation. If the company's PKI infrastructure was built on Windows 2000 the administrators may want to improve their environment with new functionality built in to Windows Server 2003.

With the advancements in Windows Server 2003's Certificate Services and Group Policies much of the administrator's time, planning, effort, and wishes will finally pay off. Creating and issuing certificates to computers and users has become much easier to deploy and ultimately to maintain and manage.

Using Windows Server 2003 Updates

Administrators have at their disposal a very cost-effective platform to deploy a PKI infrastructure on Windows Server 2003. The new features that are available with this product are as follows :

• Cross Certification. The Certificate Services in Windows Server 2003 has demonstrated full compliance with the U.S. Federal Bridge Certificate Authority (FCBA) requirements. The FCBA is a nonhierarchical PKI architecture that permits heterogeneous PKIs from different U.S. government agencies to be cross-certified and interoperate between organizations. This feature creates a certificate trust path between participating domains.

• Flexible Certificate Templates. Windows Server 2003 supports both the Windows 2000 (version 1) and the new version 2 templates. Management of the templates is controlled through the new Certificate Templates MMC snap-in. This new tool enables administrators to control template properties (such as key size and renewal period), permit autoenrollment and autorenewal for both users and machines, set access control on certificate templates to determine which users or machines can enroll for certificates, and allow for specific Cryptographic Service Provider (CSP) use and key size.

• Certificate Autoenrollment. Administrators can specify the types of certificates a user or machine can automatically receive on logon. If the access controls permit, a Windows XP or Windows Server 2003 client can access the templates in Active Directory and enroll for their respective certificates.

• Autorenewal. Administrators can use the new templates to permit the autorenewal of a user or machine certificate. This removes the administrative overhead of managing certificate expiration.

• Role-based Administration. Windows Server 2003 makes it possible to enforce the separation of the many administrative roles for the CA and operating system. With different roles no single user can compromise the entire CA.

• Key Counting. The CA now supports key counting, where the CSP maintains a count of each use of the signing key. This feature provides additional audit information that can be used to track private key distribution.

• Key Archival. The CA now has the ability to archive the keys that are associated with the certificates it issues. These keys can now be recovered using the new key recovery agent certificate.

• Delta Certificate Revocation Lists (CRL). The CA can now provide delta CRLs that are in compliance with IETF RFC 2459. This reduces the CRL network traffic because the complete replication of the full CRL database is not required for a small number of certificate revocations.

• Event Auditing. Most events that occur on the CA server can be audited . This provides a useful logging and monitoring function. Examples of this are tracking role changes, key recovery, certificate issuance, and revocation of certificates.

Choosing the CA Roles

Administrators have many choices in their enterprise security architecture. One of the choices related to PKI and smartcard secured access is the deployment of the CA roles within their organization:

• Enterprise Root CA

• Enterprise Subordinate CA

• Standalone Root CA

• Standalone Subordinate CA

The Server Does Not Have to Be a Domain Controller

Administrators can install an Enterprise CA on any domain member server. The server does not have to be a domain controller. This practice is especially important for security concerns and separating CA roles.

The most important CA role, as it relates to smartcard deployment, is the Enterprise Root CA. The Microsoft Windows Server 2003 Enterprise CA has the following characteristics:

• The Enterprise CA must be a member of a Windows Server 2003 Active Directory domain.

• The Enterprise Root CA certificate is automatically added to the Trusted Root Certification Authorities node for all users and computers in the domain.

• User certificates can be issued that allow users to log on to the Active Directory domain using computer-stored certificates and/or certificates stored on smartcards.

• User certificates and the Certificate Revocation List (CRL) are stored in the domain's Active Directory.

• Unlike Standalone CAs, an Enterprise CA issues certificates via certificate templates that can be added and customized by the CA administrator.

• Unlike the Standalone CA, the Enterprise CA confirms the credentials of the user requesting a certificate.

• The Computer or User name (also known as the Subject) can be entered manually or automatically on the certificate.

For Administrators to Enable Support of Certificate Autoenrollment...

For administrators to enable support of certificate autoenrollment, the Enterprise CA must be installed on either a Windows Server 2003 Enterprise or Datacenter Edition server.

Using the Web Enrollment Site to Obtain Certificates

Users and computers that are not domain members , or don't support autoenrollment, can use the Web enrollment site to obtain certificates.

The Enterprise CA is an ideal solution for a network with a Windows Server 2003 domain. All domain members can be assigned certificates via Group Policy “based certificate autoenrollment. You can limit the scope of autoenrollment by assigning permissions to the certificate template.

Incorporating Smartcards

By using the security access philosophy of "Something you know, something you have, and something you are," information technology administrators can significantly increase their network security. The more you can do to keep people from impersonating valid log-in attempts, the more secure the data and network resources will become. To detail the best practices that lead to secured information system access, the three items are as follows:

• Something you know. This can either be a strong password, or in the case of a smartcard this would be the user's personal identification number (PIN).

• Something you have. This is any of several devices that contain a copy of the user's PKI certificate. Examples are smartcards and USB keys.

• Something you are (optional). This refers to some physically unique attribute of the user. Examples are DNA, fingerprints , facial features, or the iris of the user's eye.

Securing Log-ins

End users in a less than secure environment can easily use someone else's username and password. This is especially open to attack when the impersonator is coming from a remote location. No one is watching the attacker sit at a remote terminal and access all the company's data.

By using a physical device such as a smartcard, secure ID, or other device, administrators can be more assured that users are actually who they say they are when they log-in.

The machines that are authenticated in Active Directory are usually known entities. This piece of information gives you a good idea of where the user is logging in from.

Securing E-mail

Sending certified, or signed, e-mail in an application such as Outlook can be performed using smartcards. Using certificates stored on the smartcard to sign the end-user's e-mail enables the recipient to know that the sender is who he actually says he is. Certificates can also be used to make sure that only the intended recipient can open and read the e-mail sent.

Securing Documents

Encrypted File System (EFS) can be employed to secure sensitive company data. This is especially critical for administrators who are tasked with protecting data on laptops and other portable devices.

Windows Server 2003 now supports EFS on offline folders and multiple user access. It is also harder for unauthorized recovery of EFS folders by third parties. EFS renders the data unreadable to anyone who is not granted access to that content.

Securing Buildings

Smartcards can be incorporated into a company's identity badge that has a radio frequency identification (RFID) capability. Card readers can be installed on the exterior, or on critical access internal doors.

Maintaining an accurate record of smartcard holders and what level of access they have can be extremely useful. All entry accesses can be centrally logged and can be audited by the administrator or security personnel.