Exam CS0-003 topic 1 question 377 discussion

The best answer is D, as nessus is an automated tool that guarantees requests will not be malformed.

Nessus can be tuned for sensitive environments — and in some ICS contexts, it’s appropriate with the right care. But in terms of safest possible method, especially when you don’t know how fragile the systems are, the manual approach (nc) remains best.

Use Nessus with restricted concurrent connections.

Nessus with restricted concurrent connections means configuring Nessus to limit the number of simultaneous connections it makes to the target systems during a scan. This is important for avoiding overwhelming sensitive systems, particularly in environments like critical infrastructure or ICS (Industrial Control Systems), where services may break or become unstable if they receive too many requests at once or requests that are too large.

Manual banner grabbing with netcat (nc) lets the analyst send minimal, carefully crafted inputs to elicit a service banner. This minimizes the risk of accidentally sending a request that could disrupt operations.