PhasorSec: Protocol Security Filters for Wide Area Measurement Systems

The addition of synchrophasors to the power grid to improve observability comes at the cost of an increased attack surface: the wide area measurement system. A common source of zero-days, that can be used to exploit the system, is improper input validation. The strict availability and timing requirements of the grid make it critical that input validation be done right and in a timely fashion. PhasorSec is a hardened security filter for the synchrophasor communication protocol, C37.118. PhasorSec is built using language theoretic principles which treat all input as a language with a specific grammar that defines what input must be accepted. An open-source version of the prototype is provided and evaluation in terms of CPU-time show that it is possible to meet the strict latency requirements. Experiments also demonstrate its effectiveness against the state-of-the-art AFL fuzzer.