vRealize Network Insight Cloud is a pre-hardened and secured appliance. vRealize Network Insight Cloud is hardened against well-established and industry-accepted security benchmarks, for example: CIS. Additionally, VMware security team has put internal controls to minimize the security footprint.
For any critical known vulnerabilities that require immediate action, VMware releases security advisories for those vulnerabilities with step-by-step instructions on how to keep the appliance secure. In general, all known vulnerabilities are fixed in every release. Use the latest version of the appliance to take advantage of these security fixes.