Domestic Power-line Communication (PLC) devices are used to extend a LAN network as well as WiFi does, but using the power-line support. Even if PLC have a bad reputation because of few aspects in the past (bad security, bad speed, not stable because of perturbations, ...), this technology grown up and offers a better connection, more stable with an encrypted conversation between two PLC devices. Someone who wants to extend his private network easily without additional wires, or without spending a 'fortune' on wireless repeaters, will use PLCs. Moreover, Internet Service Providers in France usually provide a HomePlugAV embedded in the power supply of their routers and set-top-boxes. As HomePlugAV is implemented on a lot of devices, we were interested to study their security, and their weaknesses. In this talk, we will see how PLC work with a detailed network analysis. Then we will discover few practical attacks to penetrate, and backdoor a private LAN.