Long Term Evolution (LTE) is the latest 3GPP mobile network standard, offering an all-IP network with higher efficiency and up to ten times the data rates of its predecessors. Due to an increase in cyber crime and the proliferation of mobile computing, attacks stemming from mobile devices are becoming more frequent and complex. Mobile malware can create smart-phone botnets in which a large number of mobile devices conspire to perform malicious activities on the cellular network. It has been shown that such botnets can cause a denial of service (DoS) by exhausting user traffic capacity over the air interface. Through simulation and with studies in a real-world deployment, this paper examines the impact of a botnet of devices seeking to attack the LTE network using different types of strategies. We quantify the adverse effects on legitimate users as the size of the botnet scales up in both sparsely and denselypopulated cells for varying traffic Quality of Service (QoS) requirements. Our results show that a single attacker can drastically reduce the QoS of legitimate devices in the same cell. Furthermore, we prove that the impact of the attack can be optimized by tuning the attack strategy, leveraging the LTE uplink MAC scheduler.