The paper reveals features of energy depletion attacks, which autonomously operating wireless devices are subject to. As practice shows, an attacker needs only basic technical skills, tools and resources to perform energy depletion attacks, and they are usually regarded as quite effective. The attacker can deplete the device's energy entirely rapidly, causing the attacked device to become completely disabled. The difficulty of detecting such attacks is associated with a lack of tools for monitoring energy consumption of devices in connection with identifying potentially harmful activities. In the paper modeling, experiments and analysis of a certain type of energy depletion attacks on a wireless sensor network are performed. A feature of the modeled attack is that the intruder acts with the help of a parasitic module on a certain legitimate node, which is used by the intruder as an intermediary zombie node directly attacking other nodes and depleting their energy resources.