Researchers from North Carolina State University have developed a way to measure how badly a Wifi network would be disrupted by different types of attacks.
The information could be used to help design more effective security systems, they say.
Dr Wenye Wang, an assistant professor of electrical and computer engineering, and her team examined two generic Wifi attack models. One represented persistent attacks, where the attack continues non-stop until it can be identified and disabled.
The second represents an intermittent attack, blocking access on a periodic basis, making it harder to identify and stop. The researchers compared how these attack strategies performed under varying conditions, such as with different numbers of users.
After assessing the performance of their models, the team created a metric called an ‘order gain’. This compares the probability of an attacker having access to the Wifi network to the probability of a legitimate user having access.
For example, if an attacker has an 80 percent chance of accessing the network, and other users have the other 20 percent, the order gain would be four – because the attacker’s odds of having access are four to one.
The metric’s important because a Wifi network can only serve one computer at a time, and normally functions by rapidly cycling through multiple requests. Attacks work by giving the attacker greater access to the network, effectively blocking other users.
“If we want to design effective countermeasures, we have to target the attacks that can cause the most disruption,” says Wang. “It’s impossible to prevent every conceivable attack.”
As a result, the researchers suggest that countermeasures should focus on continuous attacks that target networks with large numbers of users – because that scenario has the largest order gain.