Cybersecurity in PLC Systems – Advanced 25 MCQ Quiz

Explanation: Anomaly-based IDS finds strange traffic that could mean attacks, which is different from firewalls or patching systems.

Explanation: Before being put into production, patches should be tested in test settings to make sure they don’t cause any problems.

Explanation: Validated vendor sources make sure that the software is real and lower the chance of viruses. Pirated or cracked versions are very dangerous.

Explanation: Authentication logs that show repeated failed login attempts are a good sign that brute force assaults are happening.

Explanation: SL tells you how strong the security is against attackers with different levels of skill (accidental, purposeful, or sophisticated persistent).

Explanation: OPC UA includes built-in security features like TLS and certificates, while Modbus and Profibus do not.

Explanation: Integrity checks make ensuring that backups aren’t changed. Copying alone doesn’t guarantee safety.

Explanation: Integrity checks make ensuring that backups aren’t changed. Copying alone doesn’t guarantee safety.

Explanation: Jump servers are secure gateways that govern and keep track of who can access the PLC environment.

Explanation: USB sticks are a typical way for hackers to get in (for example, Stuxnet). Limiting use avoids illnesses that happen by mistake or on purpose.

Explanation: USB devices can send malware straight to PLCs. Untrained operators are a risk, but direct access to vendors is also a concern that is often missed.

Explanation: USB devices can send malware straight to PLCs. Untrained operators are a risk, but direct access to vendors is also a concern that is often missed.

Explanation: To figure out what happened during an attack, you need accurate timestamps. Time sync is not as much about the speed of I/O or scan cycles.

Explanation: Active scanning can mess up PLCs. Passive techniques and offline lab testing lower risk while still finding weaknesses.

Explanation: Change management with versioning finds changes to logic that aren’t allowed, while IDS watches traffic but not code.

Explanation: Zero Trust means that you can’t trust anyone by default. Every device or user must prove who they are all the time, even on the industrial network.

Explanation: If PLCs are directly connected, IT-side compromises can propagate to OT systems, which means they don’t have to be isolated. Latency and power are not as important as other things.

Explanation: Modbus TCP is a common protocol, yet it sends commands in plain text without any security. There is built-in security in OPC UA, HTTPS, and SFTP.

Explanation: Controlled jump servers, MFA, and monitoring are all used to make secure access possible. Attackers can get to PLCs through direct VPN, open ports, and cloud services that don’t have any limits.

Explanation: WAC makes ensuring that only authorized apps can operate, which stops malware from running in industrial control systems where antivirus software may not be appropriate.

Explanation: Outdated firmware typically has security holes that haven’t been fixed, which makes PLCs vulnerable to attacks. Hardware becoming outdated and not working as well as it used to are problems, but security dangers are the most important.

Explanation: Defense-in-depth uses many levels of protection, such as network segmentation, firewalls, user authentication, patching, and intrusion detection, to make sure that there is no single point of failure.

Explanation: Stuxnet took use of weaknesses in Siemens Step7 software and changed PLC code in nuclear plants. WannaCry and NotPetya are types of ransomware that attack IT systems. Duqu, on the other hand, is a type of information collecting that is related but not the same.

Explanation: A DMZ keeps business IT and OT systems apart and hosts servers (such historians and patch management) while also protecting PLCs from outside attacks.

Explanation: Network segmentation keeps important control devices apart, which stops threats from moving sideways. Flat networks and shared switches make things more dangerous, and open wireless access is quite unsafe.