Types of Wireless Network Attacks: Jamming

Since RF (radio frequency) is essentially an open medium, jamming can be a huge problem for wireless networks. Jamming is one of many exploits used compromise the wireless environment. It works by denying service to authorized users as legitimate traffic is jammed by the overwhelming frequencies of illegitimate traffic. A knowledgeable attacker with the right tools can easily jam the 2.4 GHz frequency in a way that drops the signal to a level where the wireless network can no longer function.

The complexity of jamming is the fact that it may not be caused intentionally, as other forms of wireless technology are relying on the 2.4 GHz frequency as well. Some widely used consumer products include cordless phones, Bluetooth-enabled devices and baby monitors, all capable of disrupting the signal of a wireless network and faltering traffic.

The issue of jamming mostly relates to older wireless local area networks as they are not fully equipped to make the adaptation to numerous types of interference. These networks typically call for an administrator to manually adjust each access point through trial and error. To avoid this daunting task, the best practice is to invest into a newer WLAN system. These environments offer real-time RF management features capable of identifying and adapting to unintentional interference.

Jamming Solutions

If an attacker truly wanted to compromise your LAN and wireless security, the most effective approach would be to send random unauthenticated packets to every wireless station in the network. This exploit can be easily achieved by purchasing hardware off the shelf from an electronics retailer and downloading free software from the internet. In some cases, it is simply impossible to defend against jamming as an experienced attacker may have the ability to flood all available network frequencies.

If the major concern relates to malicious jamming, an intrusion prevention and detection system may be your best option. At the bare minimum, this type of system should be able to detect the presence of an RPA (Rogue Access Point) or any authorized client device in your wireless network. More advanced systems can prevent unauthorized clients from accessing the system, alter configurations to maintain network performance in the presence of an attack, blacklist certain threats and pinpoint the physical location of a rogue device to enable faster containment.

It doesn't what type of interference you're experiencing; the network must have the ability to detect it, react and quickly make adjustments.

Identify the Presence of the Jammer

To minimize the impact of an unintentional disruption, it is important the identify its presence. Jamming makes itself known at the physical layer of the network, more commonly known as the MAC (Media Access Control) layer. The increased noise floor results in a faltered noise-to-signal ratio, which will be indicated at the client. It may also be measurable from the access point where network management features should able to effectively report noise floor levels that exceed a predetermined threshold. From there the access points must be dynamically reconfigured to transmit channel in reaction to the disruption as identified by changes at the physical layer. For example, if the attack occurred on an RF corresponding to channel 1, the access point should switch to channel 6 or 11 in order to avoid the attack. However, selecting a different channel does not always eliminate the issue of interference. An experienced attacker will often use all available channels in the attack. When this happens, your only option may be to physically hunt down the attacker and confront them face to face.

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