What is the Attack? Trimble Cityworks contains a deserialization vulnerability. This could allow an authenticated user to perform a remote code execution attack against a customer's Microsoft Internet Information Services (IIS) web server, potentially resulting in downtime and potential loss of service. According to Trimble Cityworks website, it provides a Geographic Information System (GIS)-centric solution for local governments, utilities, airports, and public works agencies to manage and maintain infrastructure across the full lifecycle. Trimble has investigated customer reports of hackers exploiting the vulnerability to gain unauthorized access to networks, confirming that active exploit