AWSOverview
The Network Access Control List (NACL) function provide stateless filtering of ingress and egress network traffic to AWS resources. It is recommended that no NACL allows unrestricted ingress access to remote server administration ports, such as SSH to port 22 and RDP to port 3389, using either the TCP (6), UDP (17) or ALL (-1) protocols.
Rationale
Public access to remote server administration ports, such as 22 and 3389, increases resource attack surface and unnecessarily raises the risk of resource compromise.
Remediation guidance
From Console:
- Open the Network ACL in the AWS management console using the
Open in AWSbutton. - Click the
Inbound Rulestab. - Click
Edit inbound rules. - Either update the Source field to a range other than 0.0.0.0/0, or remove the offending inbound rule.
- Click
Save.
Service-wide remediation
Recommended when many resources are affected: fix the platform baseline first so new resources inherit the secure setting, then remediate the existing flagged resources in batches.
AWS
Use AWS Organizations guardrails, AWS Config rules or conformance packs where they fit, approved account baselines, and IaC modules so new resources inherit the secure setting.
Operational rollout
- Fix the baseline first at the account, subscription, project, cluster, or tenant scope that owns this control.
- Remediate the currently affected resources in batches, starting with internet-exposed and production assets.
- Re-scan and track approved exceptions with an owner and expiry date.
Query logic
These are the stored checks tied to this control.
No Network ACLs allow ingress from 0.0.0.0/0 to remote server administration ports
Connectors
Covered asset types
Expected check: eq []
networkAcls(where:{rules_SOME:{AND:[{direction:"Inbound"},{action:"Allow"},{OR:[{sources_INCLUDES:"cidr:0.0.0.0/0"}, {sources_INCLUDES: "cidr:::/0"}]},{OR:[{destFromPort_LTE: 22, destToPort_GTE: 22}, {destFromPort_LTE: 3389, destToPort_GTE: 3389}]}]}}){...AssetFragment}
