What does it mean if a target is described as 'vulnerable'?

When a target is described as 'vulnerable,' it specifically indicates that it has inadequate security measures in place. This suggests that the target is susceptible to attacks or breaches because the defenses protecting it are insufficient to thwart potential threats. In an aviation security context, a vulnerable target could be a checkpoint, an airport facility, or even specific individuals who may not have adequate protective measures, making them easier targets for malicious actors.

The other options, while they describe various characteristics of targets, do not align with the definition of vulnerability in a security context. A target that is widely recognized and popular might attract attention but doesn’t inherently mean it has weaknesses in its security. Similarly, being heavily guarded implies strong security measures, which contradicts the idea of vulnerability. Lastly, having a large number of users does not affect the security of the target; it simply indicates its usage or popularity, not its defensive capabilities.