Infrastructures can be monitored by using complex IT architectures involving also the usage of UAVs. UAVs may operate by forming ad-hoc networks and may be integrated with advances sensors, like LIDAR (Light Detection and Ranging) to build a digital model of the infrastructure. Starting from a previous experience of application of this approach to monitoring road infrastructures, in this paper, we analyze the security issues of such approaches, by identifying three categories of attacks, namely (1) attacks on routing, (2) attacks on measurements, and (3) UAV impersonation. For all these attacks, we identify a possible trust-based approach to mitigate the risk. This kind of approach allows us to improve the resilience of the system and can be combined with standard cybersecurity protection mechanisms.