Over the years, modern Industrial Control Systems (ICS) have become widely computerised and connected via the Internet and are, therefore, potentially vulnerable to cyber attacks. Currently there is a lack of vulnerability scanners specialised to ICS settings. Systems such as PLCScan and ModScan output pertinent information from a Programmable Logic Controller (PLC). However, they do not offer any information as to how vulnerable a PLC is to an attack. In this paper, we address these limitations and propose SimaticScan, a vulnerability scanner specialised to Siemens SIMATIC PLCs. Through experimentation in a comprehensive water treatment testbed, we demonstrate SimaticScan’s effectiveness in determining a range of vulnerabilities across three distinct PLCs, including a previously unknown vulnerability in one of the PLCs. Our experiments also show that SimaticScan outperforms the widely used Nessus vulnerability scanner (with relevant ICS-specific plugins deployed).