Selective forwarding attack is one of well-known denial-of-service (DoS) attacks, and designing its countermeasure is critical and challenging. Detecting a forwarding misbehavior in multi-hop networks is non-trivial because it is hard to filter from node failure or packet collision. This paper proposes a new countermeasure, called camouflage-based active detection, in a rapidly emerging energy harvesting motivated networks (EHNets), where a set of self-sustainable nodes communicate directly or indirectly via multi-hop relays. Four adversarial scenarios motivated by energy harvesting and their potential forwarding vulnerabilities are analyzed. Each node actively disguises itself as an energy harvesting node, monitors any forwarding operation, and detects forwarding misbehaviors of lurk deep malicious nodes in EHNets. Extensive simulation experiments using OMNeT++ show that the proposed approach is highly detection-efficient compared to a hop-by-hop cooperative detection scheme in terms of detection latency and detection rate.