Eaton MTL

MTL Instruments Group



Tofino™ Enforcer™ revolutionises Modbus TCP/IP security

2008 10 13
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For the first time in the history of industrial automation, a security module designed specifically for managing the leading SCADA protocol, Modbus TCP, is commercially available. Byres Security Inc. and MTL Instruments, a division of Cooper Crouse-Hinds, today are introducing the Tofino™ Modbus TCP Enforcer™ Loadable Security Module (LSM), which performs detailed analysis and filtering of all Modbus TCP messages, and is certified by Modbus-IDA. It allows owners of control and SCADA systems to regulate Modbus network traffic to a level of detail that has never before been possible, thereby increasing network security, reliability and performance of critical systems.

“The ability to filter individual MODBUS commands has tremendous potential to improve the security of our control networks” stated Daniel Lacroix, Corporate Information Security Officer for The Saint Lawrence Seaway Management Corporation (SLSMC). The SLSMC operates over 30 locks and bridges on the Canadian side of the Saint Lawrence Seaway, a major marine transportation system that carried over 43 million tonnes of cargo in 2007.

“Deep packet” or “content” inspection for web email or traffic has been offered in IT firewalls for several years, but nothing has been available for the process control or SCADA world. Modbus traffic could either be allowed or blocked by a standard firewall, but fine-grained control was impossible. And since the smooth flow of Modbus TCP traffic is critical to the average industrial facility, engineers usually opted to let everything pass and take their chances with security. Industry experts have been urgently calling for better control of SCADA protocols. This spring a major US Government agency warned major energy companies:

“A vulnerability has been identified and verified within the firmware upgrade process used in control systems deployed in Critical Infrastructure and Key Resources (CIKR) development of a mitigation plan is required to protect the installed customer base and the CIKR of the nation. Firmware Vulnerability Mitigation Steps [includes] blocking network firmware upgrades with appropriate firewall rules.”

Two major energy companies and a major transportation company have trialled the Tofino™ Modbus™TCP Enforcer™ LSM and have been very excited with how it allows them to follow the government’s guidance and enhance both the security and stability of their systems. They have been able to restrict Modbus functions in numerous ways:

  • Blocking all firmware upgrades, while allowing normal HMI traffic.

  • Tailoring appropriate Modbus access permissions to PLCs for different stations, such as read-only for monitoring panels, read/write for HMIs, and full programming and diagnostics access for PLC engineering workstations.

  • Restricting Modbus access permissions to specific memory locations in a controller

  • Providing enhanced security and protection for any Modbus TCP device, including filtering of invalid traffic that could cause denial of service or system failures.

  • Enforcing read-only access to Safety Instrumented Systems for enhanced isolation and safety.

“The ModbusTCP Enforcer™ is another key step in our Tofino™ Zone Level Security™ strategy”, notes Eric Byres, CTO at Byres Security Inc. “Tofino™ provides tailored protection for groups of PLCs, DCSs RTUs and HMIs and does it in a way that is simple to implement for control engineers. Security is taken care of, and focus can be maintained on keeping processes running safely and efficiently.”