Handbook of Local Area Networks, 1998 Edition:LAN Security Click Here! Search the site:   ITLibrary ITKnowledge EXPERT SEARCH Programming Languages Databases Security Web Services Network Services Middleware Components Operating Systems User Interfaces Groupware & Collaboration Content Management Productivity Applications Hardware Fun & Games EarthWeb sites Crossnodes Datamation Developer.com DICE EarthWeb.com EarthWeb Direct ERP Hub Gamelan GoCertify.com HTMLGoodies Intranet Journal IT Knowledge IT Library JavaGoodies JARS JavaScripts.com open source IT RoadCoders Y2K Info Previous Table of Contents Next Single Sign-On The search for an enterprisewide, single sign-on technology has not yet yielded mature solutions, although several incomplete solutions, including Kerberos, have been proffered. These methodologies, based on the concept of a trusted server, are similar in nature. Kerberos establishes an exchange of access tickets or certificates between users and servers. The user requests a token and the token is issued to a specific server on a specific machine. The token is Data Encryption Standard (DES) encrypted using a key derived form the user’s password, so intruders cannot impersonate a legitimate user. At the time of this writing, Kerberos is the de facto standard, having been endorsed by several standards bodies. Regardless of the specific solution, an organization’s communications policy should enforce consistency of baseline controls to prepare for implementation of single sign-on. COMPONENTS OF THE NETWORK SECURITY POLICY The success of the network security policy depends on how well the purpose and scope of the policy are defined and communicated to employees. The policy should therefore begin with a brief statement of intent that clearly communicates the importance of security as a matter of corporate principle. The scope of the security policy defines the specific resources that must be protected and the extent of protection that is to be provided. For example, the scope of the policy might be defined as follows: This policy, while predominantly directed toward a client/server architecture, addresses any configuration that may include one or more networked microcomputers, work stations, host computers, routers, communications servers, file servers, network communications lines, dial-up access devices, wide area networks, and application firewalls. As computing and communications systems become more complex, it can be expected that the scope of the security policy will need to be broadened. For example, as more employees use Internet browsers at the desktop, more attention must be paid to these devices. In addition to specifying the types of resources to be protected, the policy should also address how different security classifications of data should be handled. For example, some organizations declare that maximum control must be provided for computing resources that process, store, and transmit information for which there is a risk that: •  Company assets might be misappropriated. •  Privacy legislation might be violated. •  Loss of systems and related data might impair the ongoing operations of the company. Exhibit 8-2-1 is a sample security policy for a networked computing environment. Exhibit 8-2-1.  Sample Information and Communications Security Policy Exhibit 8-2-1. (Continued)   Exhibit 8-2-1. (Continued)   Exhibit 8-2-1. (Continued)   Physical and Facility Security Physical protection of equipment is an essential element of the security program and its related policies. The network encompasses a substantial array of computing devices, including file servers, gateways, bridges, network control centers, routers, and concentrators. Security risks include inadvertently or intentionally cut cables, unauthorized access to network components and wiring closets, tapping of voice and fax signals, and unauthorized use of diagnostic tools. Physical access to essential networking equipment must also be controlled. Wiring cabinets and telephone terminal boxes, for example, are vulnerable to accidental or intentional abuse. The anecdote about the janitor who unplugged the power to the LAN in order to use his vacuum cleaner is not uncommon. Such network hardware components as bridges and routers are computers in their own right and as such are vulnerable to compromise. An unlocked wiring cabinet can serve as a convenient place to covertly connect a laptop to an unused port on an Ethernet hub. Such communications links as coaxial cable are also vulnerable to, for example, someone tapping the wire or monitoring the flow of traffic. Enhanced protection of the physical wiring cables that connect network and computing hardware can be achieved by putting it in a reinforced conduit. Routine inspection can help ensure that the cables have not been tampered with. Network Documentation A complete and accurate description of the network architecture, topologies, and nodes is necessary for proper network management and control, especially because networking technologies evolve so rapidly and configurations change so routinely. The origin of incoming circuits should be documented and changes to the network configuration should be certified and audited at least annually. It should be verified that out-of-service lines have been disconnected. Complete network documentation should contain network configuration drawings, a listing of vendors and support services, diagrams of cable layouts, and a complete inventory of equipment, including the physical location of resources. Network Diagnostic Tools Network diagnostic tools, commonly known as sniffers, are useful for network management. Because these same tools can be used by unscrupulous persons to obtain such data as passwords, the policy should specify that the distribution and use of diagnostic equipment be closely monitored and controlled. Data Backup Data backups can be more complex on networked processors. For example, data bases may exist on multiple servers with different backup measures. Full system backups of the contents of file servers should be performed at least weekly. Backup media should be stored in a secured area, preferably off-site if the data is critical to the operation of the organization. Power Regulation and Supply A major objective is to ensure that the network is physically protected from natural disasters. Studies indicate that a major source of data loss is electrical power fluctuations. A typical US computer installation is hit by 264 power sags and 128 power surges each year. The failure of any one network component can negatively affect the entire network. Therefore, the communications policy should require that uninterruptible power supplies, surge suppressors, or voltage regulators be installed to provide environmental assurance for these components. Business Resumption Resumption planning must include the effective coordination and integration of essential communications resources and ensure that business resumption following a disruption is as unobtrusive as possible. Having data backed up or having an uninterruptible power supply does not ensure complete protection from such disasters. Effective protection requires being able to quickly resume operations. It is therefore critical that a disaster recovery plan be written, tested, and adequately maintained. Previous Table of Contents Next Use of this site is subject certain Terms & Conditions. 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