A new security administrator ran a vulnerability scanner for the first time and caused a system outage. Which of the following types of scans MOST likely caused the outage?

A non-intrusive credentialed scan identifies vulnerabilities by inspecting internal configurations and patch levels without actively attempting exploits or stressing services, making it unlikely to cause an outage.

A non-intrusive non-credentialed scan passively identifies vulnerabilities from an external perspective without authentication and does not attempt to exploit or stress services, thus it is designed not to cause outages.

While an intrusive credentialed scan actively attempts exploits, it does so with authenticated access, which might allow for more controlled testing or less aggressive public-service probing than a non-credentialed scan, making it slightly less likely to cause a widespread outage compared to a non-credentialed one which acts purely externally.

An intrusive non-credentialed scan actively attempts to exploit vulnerabilities or aggressively test services without authenticating to the target system. This approach can send malformed packets, exploit buffer overflows, or conduct denial-of-service type tests against public-facing services, which frequently leads to system instability or outright outages on vulnerable systems.