CyberCertPrepOT Security FundamentalsOT Fundamentals: Network Architecture & ProtocolsEASYFree question
Modbus TCP is widely deployed in OT networks. Which characteristic makes it a significant security concern by default?
- A.It runs over UDP and cannot be firewalled
- B.It encrypts payloads with weak DES keys that are easily cracked
- C.It listens on TCP port 502 and provides no built-in authentication, integrity, or encryption
- D.It requires a client certificate that is rarely rotated
Why C is correct
Modbus TCP uses TCP port 502 and, like the original serial Modbus, has no authentication, integrity checking, or encryption. Any host that can reach the port can read or write coils and registers, so protection relies on segmentation, conduit firewalls, and monitoring rather than the protocol itself.
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