Use signatures or heuristics to detect malicious software. Within industrial control environments, antivirus/antimalware installations should be limited to assets that are not involved in critical or real-time operations. To minimize the impact to system availability, all products should first be validated within a representative test environment before deployment to production systems. 
Deploy anti-virus on all systems that support external email.
|ICS||T0864||Transient Cyber Asset||
Install anti-virus software on all workstation and transient assets that may have external access, such as to web, email, or remote file shares.
Ensure anti-virus solution can detect malicious files that allow user execution (e.g., Microsoft Office Macros, program installers).