Description

A denial of service vulnerability exists in the Modbus TCP and Modbus RTU over TCP functionality of Socomec DIRIS Digiware M-70 1.6.9. A specially crafted series of network requests can lead to a denial of service. An attacker can send a sequence of unauthenticated packets to trigger this vulnerability.An attacker can trigger this denial-of-service condition by sending a sequence of Modbus RTU over TCP messages to port 503 using the Write Single Register function code (6). The attack sequence begins with a message to register 58112 with a value of 1000, indicating that a configuration change will follow. Next, a message is sent to register 29440 with a value corresponding to the new Modbus address to be configured. Finally, a message to register 57856 with a value of 161 commits the configuration change. After this configuration change, the device will be in a denial-of-service state.