This chapter proposes a roadmap that employs secure parsers to eliminate the possibility of input-handling vulnerabilities in industrial control systems. Industrial control systems are responsible for maintaining the integrity of power grids. Complex communications networks constitute the backbones of these systems. Communications in industrial control networks must be processed correctly and they should not crash devices or enable attackers to access networked devices. Language-theoretic security is the practice of comprehensive input handling using secure parsers. This chapter demonstrates that the existing collection of secure parsers for industrial control protocols can cover the communications needs of industrial control networks. It discusses the merits of guarding industrial control networks using secure parsers, proposes a triage procedure for implementation and summarizes the security benefits and lessons learned.