Fuzzing tests conducted last year by customers of Synopsys, a company that provides tools and services for designing chips and electronic systems, revealed that protocols used in industrial control systems (ICS) are the least mature.
Fuzzing is a testing technique designed for finding software vulnerabilities by sending malformed input to the targeted application. If the software crashes or behaves unexpectedly, it could indicate the presence of a security flaw and further investigation is warranted. If the number of crashes is high and the time to first failure (TTFF) is short, the likelihood of exploitable vulnerabilities increases.
Synopsys’ State of Fuzzing 2017 report is based on 4.8 billion results obtained in 2016 from tests targeting 250 protocols used in industrial, Internet of Things (IoT), automotive, financial services, government, healthcare and other sectors.
In the case of ICS, Synopsys customers tested protocols such as IEC-61850 MMS, IEC-104 Server, Modbus PLC, OPC UA, DNP3 and MQTT. There are also some protocols used for both ICS and IoT, including CIP and CoAP Server.
Many of these protocols had the TTFF within five minutes. Modbus, for instance, had 37 failures after 1.5 million tests and an average test runtime of 16 minutes. The OPC UA protocol had over 16,000 failures with a testing runtime of 4.5 hours.
In comparison, the Address Resolution Protocol (ARP), which is used to convert an IP address into a physical address and is the most mature protocol, had zero failures after over 340,000 tests with an average runtime of 30 hours.
Four of the five least mature protocols, based on average TTFF, are ICS protocols, including IEC-61850 MMS, Modbus PLC, DNP3 and MQTT.
“The protocols typically associated with ICS showed the most immaturity,” Synopsys said in its report. “Many demonstrated rapid time to first failures, with IEC-61850 MMS measured in a matter of seconds. This has bearing on IoT, as many of the protocols used in ICS are also used in IoT. Clearly, more testing is needed for the protocols within ICS and IoT, as the potential for discovering more vulnerabilities is greater in these industry verticals than in others.”
The most mature protocols, based on tests conducted by Synopsys customers, are Bluetooth LE Health, DHCPv4 Client, Bluetooth LE, ARP Client, PNG and E-LMI – each with 0 failures.