Verisign Solutions for Securing Multiple Web Server and Domain Configurations

White Paper VeriSign Solutions for Securing Multiple Web Server and Domain Configurations VERISIGN SOLUTIONS FOR SECURING MULTIPLE WEB SERVER AND DOMAIN CONFIGURATIONS As organizations and service providers enhance their Web sites and extranets with newer technology to reach larger audiences, server configurations have become increasingly complex. They must now accommodate multiple domains and subdomains, load balancing requirements, and SSL digital certificates to support authentication and encryption capabilities. This paper covers the usage of VeriSign SSL certificates for organizations securing multiple Web servers and/or multiple domains and subdomains. Executive Summary For the Internet to fulfill its potential as a vehicle for commerce and electronic communications there must be a basic and commonly accepted framework for trust and security. Today, SSL certificates form that basis in most e-commerce applications, providing the following to end-users: · The Right Site: Assurance that users are indeed doing business with a particular site · The Right Company: Positive identification of the organization with which users are communicating · Company’s Ongoing Existence: Representations regarding the existence of the organization and that it is a legitimate business · Privacy: Encryption of information exchanged online To provide these functions, SSL certificates must be used in particular ways in specified configurations. Basic trust principles require careful consideration in using SSL certificates. This document clarifies the proper use of SSL certificates in special network configurations, including: 1. Redundant server backups 2. Organizations running multiple servers to support multiple site names 3. Organizations running multiple servers to support a single site name 4. Service providers using virtual and shared hosting configurations VeriSign’s recommendations for each of these scenarios involve a unique certificate per domain name per server where feasible. In shared hosting environments, VeriSign requires that service providers clearly understand both the implications involved with allowing third parties to use their certificate for securing e-commerce transactions and the limitations placed on the benefits that merchants would normally receive as part of a regular SSL certificate offering from VeriSign. To specifically address the needs of service providers with large deployments of shared hosting customers, VeriSign will soon offer a Shared SSL authentication service for individual merchants and domains that will operate from a single shared certificate. I. VeriSign Server IDs: Encryption and Authentication VeriSign is the leading supplier of trust services for the Internet and boasts the industry’s most thorough authentication practices available, as detailed in its Certification Practice Statement (www.verisign.com/repository/cps/). VeriSign is the only certification authority (CA) to pass the rigorous SAS 70 Type II Audit, which is performed annually by the consulting firm KPMG. VeriSign has been issuing SSL certificates, also called VeriSign Server IDs, since 1995. As a result, its authentication practices have evolved due to the experience of issuing nearly a quarter of a million Server IDs. VeriSign’s practices ensure that sites utilizing Server IDs can offer their Web site visitors the highest degree of security and assurances when communicating over the Internet and passing sensitive information to their Web site or server. Once an organization has satisfied VeriSign’s authentication requirements, VeriSign will issue the Server ID, which provide two essential security components: encryption and authentication. Encryption VeriSign Server IDs enable Secure Sockets Layer (SSL) technology, which encrypts communications between a Web server and a customer’s browser. SSL ensures that all communications between the client and server are virtually impenetrable to outsider attack and unavailable for any third party to access, intercept, or monitor. Authentication An equally important feature of VeriSign Server IDs is that they assure end users of the identity of the organization to which they will be providing (and hence entrusting) sensitive data. Authentication assures Internet users that they are indeed communicating with the company (and domain name) listed in the certificate, not with an imposter spoofing the Web site to steal information from unsuspecting Web site customers. Authentication also allows end users to know precisely to whom they are entrusting their confidential information. For e-commerce Web sites, authentication provides end users with the name of the company that will be responsible for processing their payment and fulfilling their order. VeriSign enables this trust between Internet merchants and their customers by following very rigorous validation procedures when issuing Server IDs. These procedures include verifying the following facts: · The company owns or has the right to use the domain name of its Web site. · The company has provided proof that it has the right to do business under the name listed in the Server ID. · The individual requesting the Server ID is authorized to a request the certificate on behalf of the organization. 3 Note: Additional restrictions are imposed on users requesting strong encryption products (128-bit SSL), as these are subject to regulations by the United States Bureau of Export Administration. VeriSign also offers its customers the NetSure Protection Plan with each Server ID. NetSure is an extended warranty program that protects VeriSign Server ID customers against economic loss resulting from the theft, corruption, impersonation, or loss of use of the VeriSign Server ID. NetSure is backed by Lloyd’s of London, one of the world's largest, A-rated insurance confederations. VeriSign Server IDs each come with up to $250,000 of NetSure Protection. VeriSign Server IDs provide the basis for trust on the Internet. VeriSign Server IDs were the first certificates commercially used on the Internet, and they are now in use at hundreds of thousands of Web sites. The importance of certificates is growing at an extremely fast rate. In fact, many state and national governments have already passed legislation that make digital signatures created with digital certificates issued through a licensed certification authority the equivalent of hand-written signatures. VeriSign is currently licensed as a CA in eight states in the United States as of March 2000. II. Multiple SSL Certificate Implementations Several important elements in a certificate help ensure security and authenticity, as shown in Figure 1. Figure 1: Important Elements in a Certificate 4 These elements contribute three fundamental trust principles to digital certificates. 1. Client applications, such as Web browsers, must be able to verify that the site the user is visiting is the site that has been certified. In practice, this means that the URL of the site matches the common name of the certificate that the site presents to the client application (usually, the site’s fully qualified domain name, such as www.samplecompany.com). 2. There must be tight binding between the organization listed in the certificate and the organization running the site. In practice, this means that the organization listed in the certificate should have the right to use the domain name in the common name and should be the entity with which the client is ultimately communicating or conducting business. It also means that the organization must have authorized the issuance of the certificate for a particular site. 3. There must be strong protection for the private key that corresponds to the certificate. In an SSL session, the client will use the public key in the certificate to send information to the server, which will ultimately be used to secure the session. Because any information encrypted with the server’s public key can be decrypted using the server’s private key, any configuration that compromises the server’s private key must be avoided. Typically, implementing digital certificates for SSL is a fairly straightforward process, as one SSL certificate is required per domain name per Web server. However, some SSL certificate implementations frequently cause confusion and sometimes violate one or more of the above fundamental principles of secure e-commerce. Private key security is fundamental to the security of SSL. Using the same certificate on multiple physical servers requires generating multiple copies of the same private key and storing those keys in multiple locations. When a private key is created and always stored in a single server, the key is reasonably well contained and auditable. When private keys are moved between servers, either by network or diskette, a new set of exposures and audit problems are created, increasing the likelihood of something going wrong and complicating the process of tracing who had access to a key in the event of compromise. Following this logic, the chance of a problem arising increases significantly in relation to the number of servers in a given deployment. Therefore, VeriSign recommends that unique private keys are used on every server in a multi-server deployment, and that the private keys are generated from the hosting server. RSA announced prescriptions for applications that are vulnerable to the adaptive chosen ciphertext attack on PKCS #1 v1.5. Prescription #1 included the recommendation that “different servers should have different key pairs.” See http://www.rsa.com/rsalabs/pkcs1/prescriptions.html,

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