Because electricity is the core of our daily lives, no one denies the massive progress we have reached thanks to such a fossil fuel-based technology. But at the same time, these advancements have costly affected our environment. Consequently, recent trends towards restructuring the electrical grids in a way intended to be more monitored, secured and environmental are brought to the forefront of the scientific research. The attempts of reconfiguring the electric power grids were coined as "smart grid". Basically, the internet, ZigBee, wireless mesh networks, WiMax, 3G, 4G, WiFi and Bluetooth are among the common communication technologies to be adopted in the framework of these smart grids alongside many emergent new technologies like the Microgrids, virtual power plants (VPPs), distributed intelligence techniques, smart metering infrastructure and demand response technology as well as distributed and renewable energy resources are conceived to make our electricity more resilient to attacks and natural disasters. As a result, the security side has become one of the major and critical associated issues. Much attention has been devoted to this domain; so, this paper aims at reviewing some of the potential attacks, threats, vulnerabilities as well as some proposed solutions to reinforce the smart grid's efficiency and reliability.