Denial of convenience attack to smartphones using a fake Wi-Fi access point

Abstract

In this paper, we present a novel denial-of-service attack targeted at popular smartphones that are used by normal users who are not technology savvy. This type of attack, which we call a denial-of-convenience attack, prevents non-technical savvy victims from utilizing data services by exploiting the connectivity management protocol of smartphones when encountered with a Wi-Fi access point. By setting up a fake Wi-Fi access point without Internet access (using a simple device such as a laptop computer), an attacker can prompt a smartphone with enabled Wi-Fi features to automatically terminate a valid mobile broadband connection and connect to this fake Wi-Fi access point. This, as a result, prevents the targeted smartphone from having any type of Internet connection unless the victim is capable of identifying the attack and manually disabling the Wi-Fi features. We demonstrate that most popular smartphones, including iPhone and Android phones, are vulnerable to denial-of-convenience attacks. To address this attack, we propose implementing a novel Internet-access validation protocol that uses the cellular network to send a secret key phrase to an Internet validation server. Then, it attempts to retrieve this secret key phrase via the newly established Wi-Fi channel to validate the Wi-Fi access point. We have fully developed and evaluated the attacks as well as the defense prototypes that run on Android phones.