Comprehensive and Detailed Explanation
The correct answer is Option C. The question asks for the immediate action to remediate the existing compliance drift, which is the VM that already has an external IP address.
Option C (Remediate): Reconfiguring the VM's network interface to remove the external IP directly fixes the identified misconfiguration. This action brings the resource back into compliance, which will cause the Security Command Center finding to be automatically set to INACTIVE on its next scan.2
Option A (Prevent): Applying the organization policy constraints/compute.vmExternalIpAccess is a preventative control.3 It will stop new VMs from being created with external IPs, but it is not retroactive and does not remove the external IP from the already existing VM. Therefore, it does not remediate the current finding.
Option B (Mask): Removing the tag simply hides the resource from the posture scan. This is a violation of compliance auditing; it masks the problem instead of fixing it.
Option D (Ignore): Marking a finding as fixed without actually fixing the underlying issue is incorrect and will not resolve the compliance drift. The finding will reappear as ACTIVE on the next scan.
Exact Extract from Google Security Operations Documents:
Finding deactivation after remediation: After you remediate a vulnerability or misconfiguration finding, the Security Command Center service that detected the finding automatically sets the state of the finding to INACTIVE the next time the detection service scans for the finding.4 How long Security Command Center takes to set a remediated finding to INACTIVE depends on the schedule of the scan that detects the findin5g.
Organization policy constraints: If enforced, the constraint constraints/compute.vmExternalIpAccess will deny the creation or update of VM instances with IPv4 external IP addresses.6 This constraint is not retroactive and will not restrict the usage of external IPs on existing VM instances. To remediate an existing VM, you must modify the instance's network interface settings and remove the external IP.
[References:, Google Cloud Documentation: Security Command Center > Documentation > Manage findings > Vulnerability findings > Finding deactivation after remediation7, Google Cloud Documentation: Resource Manager > Documentation > Organization policy > Organization policy constraints > compute.vmExternalIpAccess, , ]
