SECURITY FOR WIRELESS DEVICES AND WIRELESS NETWORKS

Many organizations and users have found that wireless communications and devices are convenient, flexible, and easy to use. Users of wireless local area network (WLAN) devices have flexibility to move their laptop computers from one place to another within their offices while maintaining connectivity with the network. Wireless personal networks allow users to share data and applications with network systems and other users with compatible devices, without being tied to printer cables and other peripheral device connections. Users of handheld devices such as personal digital assistants (PDAs) and cell phones can synchronize data between PDAs and personal computers and can use network services such as wireless email, web browsing, and Internet access. Further, wireless communications can help organizations cut their wiring costs.

While wireless networks are exposed to many of the same risks as wired networks, they are vulnerable to additional risks as well. Wireless networks transmit data through radio frequencies, and are open to intruders unless protected. Intruders have exploited this openness to access systems, destroy or steal data, and launch attacks that tie up network bandwidth and deny service to authorized users. Another risk is the theft of the small and portable devices themselves.

NIST Guidance on Security of Wireless Networks and Devices

The National Institute of Standards and Technology, Information Technology Laboratory, has published recommendations to improve the security of wireless networks in NIST Special Publication (SP) 800-48, Wireless Network Security, 802.11, Bluetooth, and Handheld Devices. Written by Tom Karygiannis and Les Owens, NIST SP 800-48 discusses three aspects of wireless security:
security issues associated with wireless local area networks (WLANs) that are based on Institute of Electrical and Electronics Engineers (IEEE) standards 802.11;
security issues related to wireless personal area networks based on the Bluetooth specifications, which were developed by an industry consortium; and
security of wireless handheld devices.

The Risk Environment

Wireless networks and handheld devices are vulnerable to many of the same threats as conventional wired networks. Intruders who gain access to information systems via wireless communications can bypass firewall protection. Once they have accessed systems, intruders can launch denial of service attacks, steal identities, violate the privacy of legitimate users, insert viruses or malicious code, and disable operations. Sensitive information that is transmitted between two wireless devices can be intercepted and disclosed if not protected by strong encryption. Handheld devices, which are easily stolen, can reveal sensitive information.

Before establishing wireless networks and using handheld devices, organizations should use risk management processes to assess the risks involved, to take steps to reduce the risks to an acceptable level, and to maintain that acceptable level of risk. Using risk management processes, managers can protect systems and information in a cost-effective manner by balancing the operational and economic costs of needed protective measures with the gains in mission capability to be achieved through the application of new technology.

Wireless Technology and Standards

Wireless devices communicate through radio transmissions, without physical connections and without network or peripheral cabling. Wireless systems include local area networks, personal networks, cell phones, and devices such as wireless headphones, microphones, and other devices that do not process or store information. Other wireless devices being widely used include infrared (IR) devices such as remote controls, cordless computer keyboards, mouse devices, and wireless hi-fi stereo headsets, all of which require a direct line of sight between the transmitter and the receiver.

Two standards for wireless technologies are discussed in NIST SP 800-48. One is the IEEE 802.11 group of standards for WLANs, which were developed by a voluntary industry standards committee. The IEEE 802.11 standards provide specifications for high-speed networks that support most of today’s applications. The Bluetooth standard, which was developed by a computer and communications industry consortium, specifies how mobile phones, computers, and PDAs interconnect with each other, with home and business phones, and with computers using short-range wireless connections.

As wireless technology evolves, new devices are being developed to provide more features, functions, portability and ease of use. Mobile phones can provide multiple services including voice, email, text messaging, paging, web access, and voice recognition services. Newer mobile phones incorporate PDA, wireless Internet, email, and global positioning system (GPS) capabilities.

Recommendations for Secure Wireless Networks

The trends in use of information technology point to increased implementation of wireless communications networks and use of wireless devices. Each new development will present new security risks, which must be addressed to ensure that critical assets remain protected. Actions that organizations should take to protect the confidentiality, integrity, and availability of all systems and information include:

Assess risks, test and evaluate system security controls for wireless networks more frequently than for other networks and systems. Maintaining secure wireless networks is an ongoing process that requires greater effort than that required for other networks and systems.

Steps that can be taken to improve the management of wireless networks include:


Maintain a full understanding of the topology of the wireless network.
Label and keep inventories of the fielded wireless and handheld devices.
Create backups of data frequently.
Perform periodic security testing and assessment of the wireless network.
Perform ongoing, randomly timed security audits to monitor and track wireless and handheld devices.
Apply patches and security enhancements.
Monitor the wireless industry for changes to standards that enhance security features and for the release of new products.
Monitor wireless technology for new threats and vulnerabilities.

Perform a risk assessment, develop a security policy, and determine security requirements before purchasing wireless technologies.

The risks associated with the use of wireless technologies are considerable, and many products provide inadequate protection. Organizations should plan to protect their essential operations before they adopt wireless technologies. Common administration problems include installing equipment with “factory default” settings, failing to control or inventory access points, not implementing the security capabilities provided, and not developing or installing security architectures that are suitable to the wireless environment. The use of firewalls between wired and wireless systems should be considered. Other good practices are to block unneeded services and ports, and to use strong cryptography. Often the risks can be addressed, but the tradeoffs between technical solutions and costs must be considered as well. Organizations may want to postpone the installation of wireless networks until more robust, open, and secure products are available.

Organizations should perform security assessments prior to implementation of wireless technologies to determine the specific threats and vulnerabilities that wireless networks will introduce in their environments. In performing the assessment, they should consider existing security policies, known threats and vulnerabilities, legislation and regulations, safety, reliability, system performance, the life-cycle costs of security measures, and technical requirements. Once the risk assessment is complete, the organization can begin planning and implementing the measures that it will put in place to safeguard its systems and lower its security risks to a manageable level. The organization should periodically reassess the policies and measures that it puts in place because computer technologies and malicious threats are continually changing.

Apply security management practices and controls to maintain and operate secure wireless networks.

Organizations should identify their information system assets, and develop, document and implement policies, standards, procedures, and guidelines to ensure confidentiality, integrity, and availability of information system resources. NIST recommends the following steps:

The information system security policy should directly address the use of 802.11, Bluetooth, and other wireless technologies.
Configuration/change control and management practices should ensure that all equipment has the latest software release, including security feature enhancements and patches for discovered vulnerabilities.
Standardized configurations should be employed to reflect the security policy, and to ensure change of default values and consistency of operations.
Security training is essential to raise awareness about the threats and vulnerabilities inherent in the use of wireless technologies.
Robust cryptography is essential to protect data transmitted over the radio channel, and theft of equipment is a major concern.