The city of tomorrow promises to facilitate online procedures, streamline traffic and optimize energy consumption. But each new digital service is also an additional opportunity for a cybercriminal to take control of it or siphon off the data collected. By offering more and more digital services, smart cities are becoming more and more connected… But also more exposed to cyber risks. The news is full of examples of communities that have been victims of ransomware, with the specter of seeing some or all of their services paralyzed. More than ever, cybersecurity is a priority issue for communities, and even more so for connected cities. This paper offers an in-depth analysis of security threats aimed at smart cities, emphasizing both cyber and physical vulnerabilities in critical infrastructures and IoT systems. It assesses existing countermeasures and suggests improvements to bolster the overall security framework, ultimately promoting safer and more resilient urban environments.