Which description best captures the common character of scan types in security assessments?

• A. External vs internal, credentialed vs non-credentialed, agent-based vs agentless, active vs passive.
• B. Internal-only scans performed with default credentials at random times.
• C. Perimeter scans only, with no credentialing and always active.
• D. Manual inspection of system configurations without tooling.

Answer: (A)

Scans in security assessments are described along multiple practical dimensions that together define how and what is tested. External versus internal indicates whether the assessment looks at systems outside the organization’s network boundary or inside it. Credentialed versus non-credentialed shows whether the scanner has login access to the targets, which matters because credentialed scans can reveal issues hidden behind authentication, such as misconfigurations and deeper vulnerabilities. Agent-based versus agentless refers to how data is collected: with software installed on each host, or by remote testing without agents, each approach offering different coverage and impact. Active versus passive describes whether the scanner actively probes systems with tests and requests, or passively observes traffic and events to infer findings.

These dimensions together capture the common character of scan types used in security assessments. The other descriptions are too narrow or unrealistic for typical practice—focusing only on internal scans with default credentials at random times, or perimeter scans with no credentialing and always active, or relying on manual inspection without tooling—because they omit other valid and common ways scans are conducted.