What does passive reconnaissance primarily involve?

Passive reconnaissance primarily involves observing and gathering information about a target without actively engaging with or probing into that target's systems or networks. This method allows an individual to collect data from publicly available sources, such as websites, social media, or public records, without alerting the target to any potential investigation.

This approach is pivotal in the early stages of reconnaissance as it helps malicious actors to build a profile of their target, including understanding their organizational structure, technologies in use, and potential vulnerabilities, all while remaining undetected. Since there is no direct interaction with the target systems, the risk of triggering alarms or defenses is significantly minimized, which is a key characteristic of passive reconnaissance.

The other options represent more active methods of information gathering or attack that would not classify under passive reconnaissance. For example, probing network vulnerabilities or scanning for open ports involves direct engagement with the target’s systems, thereby increasing the likelihood of detection. Conducting social engineering attacks also entails direct interaction with individuals in the organization, which contrasts the non-intrusive nature of passive techniques.