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Ensure no Network ACLs allow ingress from 0.0.0.0/0 to remote server administration ports

Severity: Low

Resource Types: AWS::EC2::NetworkAcl

Description​

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.

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​

From Console​

  1. Login VPC Console at VPC
  2. In the left pane, click Network ACLs
  3. For each network ACL to remediate, perform the following:
  4. Select the respective network ACL
  5. Choose the Inbound Rules tab and click Edit Inbound rules
  6. Check remote server access port entries. Note A Port value of ALL or a port range such as 0-1024 are inclusive of port 22, 3389, and other remote server administration ports.
  7. Either
    • A) Update the source field to a range other than 0.0.0.0/0 or
    • B) Click Remove the offending inbound rule
  8. Click Save changes