Question 170
A medical device uses MAB but receives an unrestricted production VLAN because a default authorization rule is too broad. Which Cisco security control or operational response BEST addresses the stated need?
Explanation
Correct Answer
Use MAC Authentication Bypass only for supported non-802.1X devices with restricted roles and inventory-backed policy. This control addresses the failure mechanism and narrows the enforcement boundary. MAB relies on spoofable MAC identity and should be treated as lower-assurance admission, not an equivalent replacement for EAP-TLS. Confirm pre-change conditions using: Inspect known endpoint MAC registrations, profiling data, switch authentication order, RADIUS policy, and allowed destination flows. Situation: A medical device uses MAB but receives an unrestricted production VLAN because a default authorization rule is too broad.
Incorrect Answers
Use Cisco Duo SSO and Adaptive Access to apply policy based on user group, application sensitivity, location or risk, and device health where supported. This response applies to Duo Adaptive Access and SSO context, not the controlling requirement in this case. Single sign-on simplifies authentication flow but does not mean every connected application should share identical authorization and risk policy. For this scenario, the targeted action is: Use MAC Authentication Bypass only for supported non-802.1X devices with restricted roles and inventory-backed policy. Situation: A medical device uses MAB but receives an unrestricted production VLAN because a default authorization rule is too broad.
Separate employee, guest, and personally owned device onboarding through Cisco ISE identity and authorization policies matched to legitimate use. This response applies to Cisco ISE guest and BYOD identity policies, not the controlling requirement in this case. Guest access and BYOD onboarding are authorization workflows, not a grant of permanent trusted access merely because a device connects to Wi-Fi. For this scenario, the targeted action is: Use MAC Authentication Bypass only for supported non-802.1X devices with restricted roles and inventory-backed policy. Situation: A medical device uses MAB but receives an unrestricted production VLAN because a default authorization rule is too broad.
Configure network access device 802.1X to use Cisco ISE RADIUS decisions and verify supplicant, authenticator, and server roles. This response applies to 802.1X port-based access with Cisco ISE, not the controlling requirement in this case. In 802.1X the endpoint supplicant communicates through an authenticator to a back-end authentication server; access policy follows AAA results. For this scenario, the targeted action is: Use MAC Authentication Bypass only for supported non-802.1X devices with restricted roles and inventory-backed policy. Situation: A medical device uses MAB but receives an unrestricted production VLAN because a default authorization rule is too broad.


