What intrusion method involves observing a victim to gather sensitive information?

The correct answer is observing a victim to gather sensitive information, commonly referred to as shouldering, or shoulder surfing. This method involves closely watching a person while they enter sensitive data, such as passwords or personal identification numbers (PINs), typically at ATMs, on computers, or while using mobile devices. By doing so, the observer collects information without any direct interaction or deception.

Phishing, on the other hand, is a technique that involves tricking individuals into providing sensitive information through fake emails or websites that appear legitimate. Blagging is more about manipulating someone into giving up information through pretense, creating a false scenario. Whaling is a targeted form of phishing aimed specifically at high-profile individuals like executives or senior management. Each of these methods relies on different tactics, whereas shouldering is explicitly about direct observation.