TrustNun is a service that compares file contents and file hashes with "known good" files from ICS/SCADA installation media.
TrustNun maintains a database of file hashes, registry changes, processes, and loaded modules for ICS/SCADA software. These artifacts were gathered from installation media and running systems. The allowlists can be used for initial triage during incident response engagements, security assessments, intrusion detection/prevention products.