TCP/UDP Protocol Network ACL Entry Allows All Ports

• Query id: f57f849c-883b-4cb7-85e7-f7b199dff163
• Query name: TCP/UDP Protocol Network ACL Entry Allows All Ports
• Platform: CloudFormation
• Severity: Medium
• Category: Networking and Firewall
• URL: Github

Description

TCP/UDP protocol AWS Network ACL Entry should not allow all ports
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - yaml file

Resources:
  MyNACL:
    Type: AWS::EC2::NetworkAcl
    Properties:
       VpcId: vpc-1122334455aabbccd
       Tags:
       - Key: Name
         Value: NACLforSSHTraffic
  InboundRule2:
    Type: AWS::EC2::NetworkAclEntry
    Properties:
       NetworkAclId:
         Ref: MyNACL
       RuleNumber: 100
       Protocol: 6
       RuleAction: allow
       CidrBlock: 172.16.0.0/24
       PortRange:
         From: 22
  InboundRule3:
    Type: AWS::EC2::NetworkAclEntry
    Properties:
       NetworkAclId:
         Ref: MyNACL
       RuleNumber: 100
       Protocol: 6
       RuleAction: allow
       CidrBlock: 172.16.0.0/24
       PortRange:
         To: 22
  InboundRule4:
    Type: AWS::EC2::NetworkAclEntry
    Properties:
       NetworkAclId:
         Ref: MyNACL
       RuleNumber: 100
       Protocol: 6
       RuleAction: allow
       CidrBlock: 172.16.0.0/24
  InboundRule5:
    Type: AWS::EC2::NetworkAclEntry
    Properties:
       NetworkAclId:
         Ref: MyNACL
       RuleNumber: 100
       Protocol: 6
       RuleAction: allow
       CidrBlock: 172.16.0.0/24
       PortRange:
         From: 0
         To: 65535

Positive test num. 2 - json file

{
  "Resources": {
    "MyNACL": {
      "Type": "AWS::EC2::NetworkAcl",
      "Properties": {
        "VpcId": "vpc-1122334455aabbccd",
        "Tags": [
          {
            "Key": "Name",
            "Value": "NACLforSSHTraffic"
          }
        ]
      }
    },
    "InboundRule2": {
      "Properties": {
        "RuleNumber": 100,
        "Protocol": 6,
        "RuleAction": "allow",
        "CidrBlock": "172.16.0.0/24",
        "PortRange": {
          "From": 22
        },
        "NetworkAclId": {
          "Ref": "MyNACL"
        }
      },
      "Type": "AWS::EC2::NetworkAclEntry"
    },
    "InboundRule3": {
      "Type": "AWS::EC2::NetworkAclEntry",
      "Properties": {
        "NetworkAclId": {
          "Ref": "MyNACL"
        },
        "RuleNumber": 100,
        "Protocol": 6,
        "RuleAction": "allow",
        "CidrBlock": "172.16.0.0/24",
        "PortRange": {
          "To": 22
        }
      }
    },
    "InboundRule4": {
      "Type": "AWS::EC2::NetworkAclEntry",
      "Properties": {
        "RuleNumber": 100,
        "Protocol": 6,
        "RuleAction": "allow",
        "CidrBlock": "172.16.0.0/24",
        "NetworkAclId": {
          "Ref": "MyNACL"
        }
      }
    },
    "InboundRule5": {
      "Type": "AWS::EC2::NetworkAclEntry",
      "Properties": {
        "CidrBlock": "172.16.0.0/24",
        "PortRange": {
          "To": 65535,
          "From": 0
        },
        "NetworkAclId": {
          "Ref": "MyNACL"
        },
        "RuleNumber": 100,
        "Protocol": 6,
        "RuleAction": "allow"
      }
    }
  }
}

Code samples without security vulnerabilities

Negative test num. 1 - yaml file

Resources:
  MyNACL9:
    Type: AWS::EC2::NetworkAcl
    Properties:
       VpcId: vpc-1122334455aabbccd
       Tags:
       - Key: Name
         Value: NACLforSSHTraffic
  InboundRule9:
    Type: AWS::EC2::NetworkAclEntry
    Properties:
       NetworkAclId:
         Ref: MyNACL
       RuleNumber: 100
       Protocol: 6
       RuleAction: allow
       CidrBlock: 172.16.0.0/24
       PortRange:
         From: 22
         To: 22

Negative test num. 2 - json file

{
  "Resources": {
    "MyNACL9": {
      "Type": "AWS::EC2::NetworkAcl",
      "Properties": {
        "Tags": [
          {
            "Key": "Name",
            "Value": "NACLforSSHTraffic"
          }
        ],
        "VpcId": "vpc-1122334455aabbccd"
      }
    },
    "InboundRule9": {
      "Type": "AWS::EC2::NetworkAclEntry",
      "Properties": {
        "Protocol": 6,
        "RuleAction": "allow",
        "CidrBlock": "172.16.0.0/24",
        "PortRange": {
          "From": 22,
          "To": 22
        },
        "NetworkAclId": {
          "Ref": "MyNACL"
        },
        "RuleNumber": 100
      }
    }
  }
}