Exam CAS-004 topic 1 question 226 discussion

I'm going with A. It directly addresses the risk of unauthorized application execution on the end-of-life operating system. C and D may not be as effective in protecting against zero-day exploits or targeted attacks that exploit vulnerabilities in an end-of-life operating system

o The best compensating control to implement on this server is a host-based firewall. o A host-based firewall provides an additional layer of security directly on the server itself. It can filter incoming and outgoing network traffic based on predefined rules, effectively blocking malicious connections and preventing unauthorized access. This is crucial in this scenario where upgrading the operating system is not feasible due to compatibility issues with the ICS software. A host-based firewall can help isolate the server from the network and minimize the potential attack surface. It can also monitor for suspicious activity on the server itself.

I think the best answer to this question is HIPS

A. I like HIPS but in an ICS the servers need to be up and running.

Application allow list, network white list, ... are the most common compensating controls

Given the constraints of the industrial control system (ICS) software being incompatible with modern operating systems, the best compensating control to protect the server running the end-of-life operating system would be: C. HIPS (Host-based Intrusion Prevention System) HIPS monitors and analyzes network traffic and system activities on individual hosts to identify suspicious behavior and prevent unauthorized access or activities. It can provide additional protection against vulnerabilities in the end-of-life operating system by detecting and blocking malicious activities in real-time. This helps mitigate the risks associated with using an unsupported operating system while maintaining the necessary functionality for the ICS software to operate.

The answer is (C) according to ChatGPT

A. Application allow list Based on the comments, this is the correct answer. Keywords: "BEST...compensating control".

The only thing that protects against 0 days in the list. It is the best option. idk why there are split voting on this...

Application allow list: This control focuses on restricting the execution of unauthorized applications, including potential malware, on the server. This is particularly relevant in ICS environments where security needs prioritize known and authorized software for process control and stability.

Throwing my weight towards A too

Going with A. You need to isolate the server to only perform what is absolutely necessary to best mitigate against Zero Day Attacks. A HIPS recognizes signatures but does not offer best protection against Zero Day.

Yep it's A

It is absolutely C. The Server is EOL, and you're stuck with it (can't upgrade). It may already have a host based firewall, it may not. Regardless, a HIPS is a comprehensive solution to secure a piece of legacy hardware that you can't get rid of without crippling your "manufacturing environment." Don't listen to everyone voting for A or D, they are lying to you. Or illiterate. Or both.

Its C, HIPS. A HIPS is the best tool available here by a mile. Application allow list? Doesn't do anything to stop an attack, only prevents users from installing malware. Antivirus? Not comprehensive enough. Host-based firewall? Not effective at actively detecting and stopping threats. It's C 1000%.

Implementing a host-based firewall is a crucial compensating control to enhance the security of a server, especially in a situation where the operating system cannot be upgraded due to compatibility issues with ICS software. Here are some key considerations for implementing a host-based firewall: Chat GPT

Controlled Network Access: A host-based firewall can be configured to control and restrict network traffic to and from the server. This helps in preventing unauthorized access and potential network attacks. Filtering Inbound and Outbound Traffic: The firewall can be configured to allow only necessary inbound and outbound network traffic, blocking any attempts by malicious actors to exploit vulnerabilities in the outdated operating system. Protecting Against Exploits: If there are known vulnerabilities in the end-of-life operating system that cannot be patched, a host-based firewall can act as a barrier, preventing exploitation of these vulnerabilities by filtering malicious traffic. Enhancing Security Posture: While not a substitute for upgrading the operating system, a host-based firewall adds an additional layer of defense by controlling network communication. It helps in reducing the attack surface and mitigating the risks associated with running an outdated OS.