webapp-securitygroup.yaml

# Note : The Cloudformation Security Group IP address is open by default (testing purpose).
# You should update Security Group Access with your own IP Address to ensure your instances security.
#
---
AWSTemplateFormatVersion: "2010-09-09"
Description: >
    This template contains the Security Groups and Network Access Control
    required by our entire stack. We create them in a seperate nested template,
    so they can be referenced by all of the other nested templates.

Parameters:

  PMServerEnv:
    Description: "Server Environment name."
    ConstraintDescription: "Choose an Environment from the drop down"
    Type: "String"
    AllowedValues: 
      - "dev"
      - "staging"
      - "prod"

  PMVPC:
    Description: "VPC to launch instances into"
    Type: "AWS::EC2::VPC::Id"

  PMNACL:
    Description: "Network ACL Id"
    Type: "String"

  PMOWNIP:
    Description: "Update this with your own office/home public ip address"
    Type: "String"


Resources:
  # This security group defines Nginx Web proxy host.
  # By default we're just allowing access from the load balancer.  If you want to SSH 
  # into the hosts, or expose non-load balanced services you can open their ports here.
  ProxyHostSG:
    Type: "AWS::EC2::SecurityGroup"
    Properties: 
      VpcId: !Ref "PMVPC"
      GroupDescription: "Web Server Security Group"
      SecurityGroupIngress:
        - CidrIp: !Ref "PMOWNIP"
          FromPort: "22"
          IpProtocol: "tcp"
          ToPort: "22"
        - FromPort: "443"
          IpProtocol: "tcp"
          SourceSecurityGroupId:
            Ref: "WEBELBSG"
          ToPort: "443"
        - FromPort: "80"
          IpProtocol: "tcp"
          SourceSecurityGroupId:
            Ref: "WEBELBSG"
          ToPort: "80"
      SecurityGroupEgress:
        - IpProtocol: '-1'
          CidrIp: '0.0.0.0/0'
      Tags:
        - Key: "Name"
          Value: !Sub "${PMServerEnv}-ProxyHostSG"

  # Web Proxy Server Elastic Load Balancer
  WEBELBSG:
    Type: "AWS::EC2::SecurityGroup"
    Properties:
      GroupDescription: "ELB-WEBSG"
      SecurityGroupEgress:
      - IpProtocol: "-1"
        CidrIp: "0.0.0.0/0"
      SecurityGroupIngress:
      - IpProtocol: 'icmp'
        FromPort: '-1'
        ToPort: '-1'
        CidrIp: '0.0.0.0/0'
      - CidrIp: "0.0.0.0/0"
        FromPort: "80"
        IpProtocol: "tcp"
        ToPort: "80"
      - CidrIp: "0.0.0.0/0"
        FromPort: "443"
        IpProtocol: "tcp"
        ToPort: "443"
      VpcId: !Ref "PMVPC"
      Tags:
        - Key: "Name"
          Value: !Sub "${PMServerEnv}-WEBELBSG"

  # App Server Security Group
  # PHP-fpm (port 9000)
  APPHostSG:
    Type: "AWS::EC2::SecurityGroup"
    Properties: 
      VpcId: !Ref "PMVPC"
      GroupDescription: "Application Server Security Group"
      SecurityGroupIngress:
        # This is private subnet, so you can only able to ssh once you're inside 
        # the public subnet host (E.g. Bastion Host).
        - CidrIp: "0.0.0.0/0"
          FromPort: "22"
          IpProtocol: "tcp"
          ToPort: "22"
        - FromPort: "9000"
          IpProtocol: "tcp"
          SourceSecurityGroupId:
            Ref: "APPELBSG"
          ToPort: "9000"
      SecurityGroupEgress:
        - IpProtocol: '-1'
          CidrIp: '0.0.0.0/0'
      Tags:
        - Key: "Name"
          Value: !Sub "${PMServerEnv}-APPHostSG"

  # AppServer Elastic Load Balancer
  APPELBSG:
    Type: "AWS::EC2::SecurityGroup"
    Properties:
      GroupDescription: "ELB-APPSG"
      SecurityGroupEgress:
      - IpProtocol: "-1"
        CidrIp: "0.0.0.0/0"
      SecurityGroupIngress:
        - FromPort: "9000"
          IpProtocol: "tcp"
          SourceSecurityGroupId:
            Ref: "ProxyHostSG"
          ToPort: "9000"
      VpcId:
        Ref: "PMVPC"
      Tags:
        - Key: "Name"
          Value: !Sub "${PMServerEnv}-APPELBSG"

  # Allow RDS connection from ProxyHostSG only.
  RDSSG:
    Type: "AWS::EC2::SecurityGroup"
    Properties:
      GroupDescription: "Security group for RDS DB Instance."
      SecurityGroupEgress:
      - IpProtocol: "-1"
        CidrIp: "0.0.0.0/0"
      SecurityGroupIngress:
      - FromPort: "3306"
        IpProtocol: "tcp"
        SourceSecurityGroupId:
          Ref: "ProxyHostSG"
        ToPort: "3306"
      VpcId:
        Ref: "PMVPC"
      Tags:
        - Key: "Name"
          Value: !Sub "${PMServerEnv}-RDSSG"


  #####################################################################################
  # Additional Firewall Protection (inbound and outbound traffic at the subnet level)
  ####### INBOUND HTTP Network ACL RULES ##############################################
  InboundHTTPNACL:
    Type: "AWS::EC2::NetworkAclEntry"
    Properties:
      NetworkAclId: !Ref "PMNACL"
      RuleNumber: '100'
      Protocol: "6"
      RuleAction: "allow"
      Egress: "false"
      CidrBlock: "0.0.0.0/0"
      PortRange:
        From: '80'
        To: '80'

  ####### INBOUND HTTPS Network ACL RULES #######
  InboundHTTPSNACL:
    Type: "AWS::EC2::NetworkAclEntry"
    Properties:
      NetworkAclId: !Ref "PMNACL"
      RuleNumber: '200'
      Protocol: "6"
      RuleAction: "allow"
      Egress: "false"
      CidrBlock: "0.0.0.0/0"
      PortRange:
        From: '443'
        To: '443'

  ####### INBOUND SSH Network ACL RULES #######
  InboundSSHNACL:
    Type: "AWS::EC2::NetworkAclEntry"
    Properties:
      NetworkAclId: !Ref "PMNACL"
      RuleNumber: '300'
      Protocol: "6"
      RuleAction: "allow"
      Egress: "false"
      CidrBlock: !Ref "PMOWNIP"
      PortRange:
        From: '22'
        To: '22'

  ####### INBOUND Ephemeral Ports Network ACL RULES #######
  InboundEPHNACL:
    Type: "AWS::EC2::NetworkAclEntry"
    Properties:
      NetworkAclId: !Ref "PMNACL"
      RuleNumber: '400'
      Protocol: "6"
      RuleAction: "allow"
      Egress: "false"
      CidrBlock: "0.0.0.0/0"
      PortRange:
        From: '1024'
        To: '65535'

  ####### INBOUND ICMP Network ACL RULES #######
  InboundICMPNACL:
    Type: "AWS::EC2::NetworkAclEntry"
    Properties:
      NetworkAclId: !Ref "PMNACL"
      RuleNumber: '500'
      Protocol: "1"
      RuleAction: "allow"
      Egress: "false"
      CidrBlock: "0.0.0.0/0"
      Icmp:
        Code: "-1"
        Type: "-1"

  ####### OUTBOUND HTTP Network ACL RULES #######
  OutboundHTTPNACL:
    Type: "AWS::EC2::NetworkAclEntry"
    Properties:
      NetworkAclId: !Ref "PMNACL"
      RuleNumber: '100'
      Protocol: "6"
      RuleAction: "allow"
      Egress: "true"
      CidrBlock: "0.0.0.0/0"
      PortRange:
        From: '80'
        To: '80'

  ####### OUTBOUND HTTPS Network ACL RULES #######
  OutboundHTTPSNACL:
    Type: "AWS::EC2::NetworkAclEntry"
    Properties:
      NetworkAclId: !Ref "PMNACL"
      RuleNumber: '200'
      Protocol: "6"
      RuleAction: "allow"
      Egress: "true"
      CidrBlock: "0.0.0.0/0"
      PortRange:
        From: '443'
        To: '443'

  ####### OUTBOUND SSH Network ACL RULES #######
  OutboundSSHNACL:
    Type: "AWS::EC2::NetworkAclEntry"
    Properties:
      NetworkAclId: !Ref "PMNACL"
      RuleNumber: '300'
      Protocol: "6"
      RuleAction: "allow"
      Egress: "true"
      CidrBlock: !Ref "PMOWNIP"
      PortRange:
        From: '22'
        To: '22'

  ####### OUTBOUND Ephemeral Ports Network ACL RULES #######
  OutboundEPHNACL:
    Type: "AWS::EC2::NetworkAclEntry"
    Properties:
      NetworkAclId: !Ref "PMNACL"
      RuleNumber: '400'
      Protocol: "6"
      RuleAction: "allow"
      Egress: "true"
      CidrBlock: "0.0.0.0/0"
      PortRange:
        From: '1024'
        To: '65535'

  ####### OUTBOUND ICMP Network ACL RULES #######
  OutboundICMPNACL:
    Type: "AWS::EC2::NetworkAclEntry"
    Properties:
      NetworkAclId: !Ref "PMNACL"
      RuleNumber: '500'
      Protocol: "1"
      RuleAction: "allow"
      Egress: "true"
      CidrBlock: "0.0.0.0/0"
      Icmp:
        Code: "-1"
        Type: "-1"


Outputs:

  ProxyHostSG: 
    Description: "A reference to the security group for Proxy hosts"
    Value: !Ref "ProxyHostSG"

  WEBELBSG:
    Description: "A reference to the security group for Web ELB"
    Value: !Ref "WEBELBSG"

  APPHostSG: 
    Description: "A reference to the security group for APP hosts"
    Value: !Ref "APPHostSG"

  APPELBSG:
    Description: "A reference to the security group for Application ELB"
    Value: !Ref "APPELBSG"

  RDSSG:
    Description: "A reference to the security group for RDS"
    Value: !Ref "RDSSG"
    Export:
      Name: !Sub "${PMServerEnv}-RDSSG"