BCN-T3-NET-002Tier 3 · Best PracticesNetwork

Cloud Network Hardening Gaps

Cloud network configuration diverging from CIS Benchmark or provider best practice.

Remediation SLA: 90 days
Tier: 3 · Best Practices
Domain: Network
Escalation: Reviewed at quarterly planning; may be formally deferred

What this finding is

Cloud network configuration departs from established benchmarks without creating direct exposure — default VPCs still present, overly broad security group rules on internal traffic, absent VPC flow logging, unused elastic IPs, or missing private endpoints for provider services.

Why it is Tier 3

These are the conditions from which Tier 1 findings emerge. A default VPC with permissive rules is the environment in which someone eventually launches an internet-facing instance by accident. Individually low-impact and each cheap to fix, they compound into the misconfigurations that appear in breach reports. Benchmark alignment also materially reduces audit friction.

Most common misclassification

Benchmark reports frequently include genuinely Tier 1 items — public storage, unrestricted administrative ingress — mixed into the same output. Triage benchmark findings individually rather than importing the whole report at Tier 3.

How to detect it

1Run a CIS Benchmark assessment with PROWLER, Cloudsploit, or ScoutSuite across every account and region.
2Check for default VPCs in unused regions, which are commonly overlooked and permissively configured.
3Identify security groups with broad internal CIDR sources rather than security-group references.
4Confirm private endpoints are used for provider services so that traffic does not traverse the public internet unnecessarily.

How to remediate it

Steps are ordered. The first step is the one that reduces exposure fastest, which is not always the one that closes the finding.

1Delete default VPCs in regions with no workloads, and restrict region usage through policy.
2Replace CIDR-based internal rules with security-group references so policy follows workloads.
3Enable flow logging on all VPCs, which also supports BCN-T2-NET-002.
4Adopt private endpoints for provider service access.
5Encode the benchmark as preventive policy so remediated items do not regress.

How to verify the fix

A benchmark assessment reports the target pass rate across all accounts and regions, with documented exceptions, and preventive policy blocks reintroduction of the corrected items.