Ad hoc low-power wireless networks are an exciting research direction in sensing and pervasive computing. Prior security work in this area has focused primarily on denial of communication at the routing or medium access control levels. This paper explores resource depletion attacks at the routing protocol layer, which permanently disable networks by quickly draining node’s battery power. These “Vampire” attacks are not specific to any specific protocol, but rather rely on the properties of many popular classes of routing protocols. The authors find that all examined protocols are susceptible to Vampire attacks, which are devastating, difficult to detect and are easy to carry out using as few as one malicious insider sending only protocol-compliant messages.