Security module addresses government SCADA concerns
Byres Security Inc. and MTL Instruments, a division of Cooper Crouse-Hinds, introduced the Tofino Modbus TCP Enforcer Loadable Security Module (LSM) at the ISA show this week in Houston, TX. The module performs detailed analysis and filtering of all Modbus TCP messages and is certified by Modbus-IDA.
“Deep packet” or “content” inspection for Web email or traffic has been offered in IT firewalls for several years, but similar capabilities have not 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 not possible, said Eric Byres, CTO at Byres Security Inc. “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,” he added.
This detailed level of analysis and filtering in SCADA systems has recently become a government-level concern. This year, the U.S. Department of Homeland Security warned: “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 [include] blocking network firmware upgrades with appropriate firewall rules.”
Two global energy companies and a major transportation company have thus far tested the Tofino ModbusTCP Enforcer LSM and are reportedly pleased 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; and
Enforcing read-only access to safety instrumented systems for enhanced isolation and safety.