Final answer:
The test used by a penetration tester to find network vulnerabilities exposed to unprivileged users is typically a Black Box test or external testing. It simulates an attack from an outsider's perspective and identifies security weaknesses.
Step-by-step explanation:
The type of test a penetration tester might use when aiming to gain a view of the network vulnerabilities exposed to unprivileged users is commonly referred to as a Black Box test or external testing.
This kind of security audit is performed without any prior knowledge of the network's infrastructure, similar to the perspective of a potential attacker. The tester uses this approach to simulate an external hacking or cyber-attack, probing the system for any discoverable weaknesses such as outdated software, misconfigurations, and improper access controls.
Penetration testing can also be approached as a White Box test (with full knowledge of the network) or as a Grey Box test (with partial knowledge), but given the scenario indicated in the question, Black Box testing is the most accurate answer as it focuses on vulnerabilities that would be visible from outside the network to unprivileged users.