Which type of scanning uses indirect methods, such as inspecting traffic flows and protocols, and is often suited for industrial or sensitive networks?

Passive scans are characterized by their ability to gather information without actively probing the network, which makes them well-suited for industrial or sensitive environments. This type of scanning inspects traffic flows and protocols without sending packets that could potentially disturb ongoing communications or raise alarms on security defenses.

By monitoring the data that passes through the network, passive scans can identify vulnerabilities and track network behavior over time without introducing additional risks. This method is particularly effective in sensitive settings where minimizing disruptions is critical, allowing security analysts to have a clearer understanding of the network without being intrusive.

In contrast, active scans involve sending specific requests or probes into the network, which can alert security systems or disrupt normal operations, making them less desirable in sensitive contexts. Third-party assessments and self-assessments typically involve more direct analysis and interaction with the system, which may not align with the need for non-intrusive methods. Thus, passive scans are often the preferred approach in environments where discretion and ongoing analysis of traffic and behavior are vital.