Malicious sources within networks are identified using bait traffic, including mobile IP messages, transmitted between a collaborating network device and a collaborating mobile client that has a fixed connection to the network. The bait traffic entices a malicious source to transmit malicious packets towards the collaborating mobile client and/or the network device. Upon receiving a malicious packet, the collaborating mobile client or the network device is able to identify the source of the packet as a malicious source and report the presence of the malicious source within the network.