Wireless Personal Area Networks (WPANs) | Bluetooth Networks

Personal area network (PAN) is a computer network designed for communication between computer devices (including telephones and personal digital assistants close to one person). The devices may or may not belong to the person in question. The reach of a pan is typically a few meters. Pans can be used for communication among the personal devices themselves or for connecting to a higher level network and the internet. Personal area networks may be wired with computer buses such as USB and firewire. A wireless personal area network (WPAN) can also be made possible with network technologies such as IrDA and Bluetooth.
 

A Bluetooth PAN is also called a piconet, and is composed of up to 8 active devices in a master-slave relationship. The first Bluetooth device in the piconet is the master, and all other devices are slaves that communicate with the master. A piconet typically has a range of 10 meters, although ranges of up to 100 meters can be reached under ideal circumstances.

Security threat and requirements of wireless PAN:

Bluetooth offers several benefits and advantages. However, organizations must not only address the security threats associated with Bluetooth before they implement the technologies; they must also measure the vulnerabilities of the devices they allow to participate in the Bluetooth networks. Specifically, agencies need to address security concerns for confidentiality, data integrity, and network availability. Moreover, since Bluetooth devices are more likely to be managed by users that are less security conscious than administrators, they are more likely to contribute to uncontrolled security drifts. This subsection will briefly cover some of the risks to security, i.e., attacks on confidentiality, integrity, and network availability.

Loss of confidentiality:

Threats to confidentiality involve, first of all, compromised Bluetooth devices. When a Bluetooth device that is part of a piconet becomes compromised (e.g., is in the possession of an unauthorized user), it may still receive information that the malicious user should not access. Moreover, the compromised device may still have network or information privileges, resulting in a compromise of the wider network as well. In the latter case, the compromised device may not only receive normal proprietary traffic but may also request that information as part of a targeted network attack. A trait of Bluetooth that makes this compromise unique is that the Bluetooth network requires device and not the user authentication to access resources. Once the device is authenticated, it is automatically connected to resources without the need for subsequent authentication. (Geoff Huston, the wireless internet)

Loss of integrity:

Infringements of integrity result from the corruption of an organization’s or user’s data. The direct effect is similar to that of a confidentiality, or disclosure, threat: a compromised network. However, integrity threats extend beyond this, involving the alteration, addition, or deletion of information, which is then passed through the network without the user’s or network administrator’s knowledge. Information that is subject to corruption includes files on the network and data on user devices. For example, a malicious user might use an un trusted device, such as a PDA, to access the address book of another PDA or laptop. However, instead of just monitoring the information, as would be the case with a disclosure threat, the malicious user alters the contact information without the owner’s knowledge or may even delete the information completely. If undetected, such attacks could result in the agency or user losing confidence in its data and system. Users should verify that their Bluetooth product does not allow automatic data synchronization to prevent the alteration of any information without the acknowledgement user of that device.

Loss of availability:

Denial of service attacks cause in the loss of network availability for authorized users and devices. Denial of service attacks block authorized user access to system resources and network applications. Besides the typical dos attacks directed against LANs and internet services, Bluetooth devices are also susceptible to signal jamming. Bluetooth devices share bandwidth with microwave ovens, cordless phones, and other wireless networks and thus are exposed to interference. Malicious users can interfere with the flow of information by using devices that transmit in the 2.4 GHz ism band. Disrupting the routing protocol prevents ad hoc network devices from negotiating the network’s dynamic topologies. Remote users may encounter jamming more frequently than on-site users. Remote users must contend with the same interference that users experience in the office. Further, since the remote environment is uncontrolled, remote devices are more likely to be in close immediacy to devices that are intentionally or unintentionally jamming their signals. Another threat associated with ad hoc devices is a battery exhaustion attack. This attack attempts to disable a device by draining its battery. A malicious user continually sends requests to the device asking for data transfers (assuming the user is part of the network topology) or asking the device to create a network. Although this type of attack does not compromise network security, it ultimately prevents the user from gaining access to the network, because the device cannot function. (juha t. Vainio, may 25, 2000)

Solutions & security measures for WPAN:

Wireless personal area network and other Bluetooth technologies are relatively new standard and have yet to become common in the marketplace. However, solutions and improvements are available to help secure WPAN networks. These measures include management solutions, operational solutions, and technical solutions

Management solutions:

The first line of protection is to provide a sufficient level of knowledge and understanding for those who will deal with WPAN & Bluetooth enabled devices & networks. Organizations using wireless personal area network technology need to establish and document security policies that address the use of Bluetooth enabled devices and the user’s responsibilities. The policy document should include a list of approved uses for WPAN’s, the type of information that may be transferred in the network, and any disciplinary actions that may result from misuse. The security policy should also specify a proper password usage scheme.

Operational solutions:

Since Bluetooth devices do not register when they join a network, they are invisible to network administrators. Consequently, it is difficult for administrators to apply traditional physical security measures. However, there are some security approaches that can be applied, including establishing spatial distance and securing the gateway Bluetooth devices that connect remote Bluetooth networks or devices. Establishing spatial distance requires setting the power requirements low enough to prevent a device operating on the organizations premises from having sufficient power to be detected outside physical boundaries. This spatial distance in effect creates a more secure boundary. Currently, Bluetooth devices have a useful range of approximately 30 feet. Organizations that require both high levels of security and low levels of security should maintain a secure perimeter so that on site network users can maintain secure connections in their office premises. Agencies with requirements for high levels of security should also restrict unauthorized personnel from using PDAs, laptops, and other electronic devices within the secure perimeter. (tom karygiannis, les Owens, nov 2002)

Technical solutions:

As with WLANs and Bluetooth technical solutions & improvements fall into one of two categories: software security solutions and hardware security solutions. Bluetooth software solutions focus on personal identification number (pin) and private authentications, while hardware solutions involve the use of the Bluetooth device address and link keys that reside at the link level. Again, it should be noted that hardware solutions, which generally have software components, are into simply as hardware solutions.