# SEC 5 How do you protect your network resources?
Any workload that has some form of network connectivity, whether it’s the internet or a private network, requires multiple layers of defense to help protect from external and internal network-based threats.
**Topics**
+ [SEC05-BP01 Create network layers](sec_network_protection_create_layers.md)
+ [SEC05-BP02 Control traffic at all layers](sec_network_protection_layered.md)
+ [SEC05-BP03 Automate network protection](sec_network_protection_auto_protect.md)
+ [SEC05-BP04 Implement inspection and protection](sec_network_protection_inspection.md)
# SEC05-BP01 Create network layers
Group components that share reachability requirements into layers. For example, a database cluster in a virtual private cloud (VPC) with no need for internet access should be placed in subnets with no route to or from the internet. In a serverless workload operating without a VPC, similar layering and segmentation with microservices can achieve the same goal.
Components such as Amazon Elastic Compute Cloud (Amazon EC2) instances, Amazon Relational Database Service (Amazon RDS) database clusters, and AWS Lambda functions that share reachability requirements can be segmented into layers formed by subnets. For example, an Amazon RDS database cluster in a VPC with no need for internet access should be placed in subnets with no route to or from the internet. This layered approach for the controls mitigates the impact of a single layer misconfiguration, which could allow unintended access. For Lambda, you can run your functions in your VPC to take advantage of VPC-based controls.
For network connectivity that can include thousands of VPCs, AWS accounts, and on-premises networks, you should use [AWS Transit Gateway](http://aws.amazon.com/transit-gateway). It acts as a hub that controls how traffic is routed among all the connected networks, which act like spokes. Traffic between an Amazon Virtual Private Cloud and AWS Transit Gateway remains on the AWS private network, which reduces external threat vectors such as distributed denial of service (DDoS) attacks and common exploits, such as SQL injection, cross-site scripting, cross-site request forgery, or abuse of broken authentication code. AWS Transit Gateway inter-region peering also encrypts inter-region traffic with no single point of failure or bandwidth bottleneck.
**Level of risk exposed if this best practice is not established:** High
## Implementation guidance
+ Create subnets in VPC: Create subnets for each layer (in groups that include multiple Availability Zones), and associate route tables to control routing.
+ [VPCs and subnets ](https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Subnets.html)
+ [Route tables ](https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Route_Tables.html)
## Resources
**Related documents:**
+ [AWS Firewall Manager](https://docs.aws.amazon.com/waf/latest/developerguide/fms-chapter.html)
+ [ Amazon Inspector ](https://aws.amazon.com/inspector)
+ [Amazon VPC Security](https://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Security.html)
+ [Getting started with AWS WAF](https://docs.aws.amazon.com/waf/latest/developerguide/getting-started.html)
**Related videos:**
+ [AWS Transit Gateway reference architectures for many VPCs ](https://youtu.be/9Nikqn_02Oc)
+ [Application Acceleration and Protection with Amazon CloudFront, AWS WAF, and AWS Shield](https://youtu.be/0xlwLEccRe0)
**Related examples:**
+ [Lab: Automated Deployment of VPC](https://www.wellarchitectedlabs.com/Security/200_Automated_Deployment_of_VPC/README.html)
# SEC05-BP02 Control traffic at all layers
When architecting your network topology, you should examine the connectivity requirements of each component. For example, if a component requires internet accessibility (inbound and outbound), connectivity to VPCs, edge services, and external data centers.
A VPC allows you to define your network topology that spans an AWS Region with a private IPv4 address range that you set, or an IPv6 address range AWS selects. You should apply multiple controls with a defense in depth approach for both inbound and outbound traffic, including the use of security groups (stateful inspection firewall), Network ACLs, subnets, and route tables. Within a VPC, you can create subnets in an Availability Zone. Each subnet can have an associated route table that defines routing rules for managing the paths that traffic takes within the subnet. You can define an internet routable subnet by having a route that goes to an internet or NAT gateway attached to the VPC, or through another VPC.
When an instance, Amazon Relational Database Service(Amazon RDS) database, or other service is launched within a VPC, it has its own security group per network interface. This firewall is outside the operating system layer and can be used to define rules for allowed inbound and outbound traffic. You can also define relationships between security groups. For example, instances within a database tier security group only accept traffic from instances within the application tier, by reference to the security groups applied to the instances involved. Unless you are using non-TCP protocols, it shouldn’t be necessary to have an Amazon Elastic Compute Cloud(Amazon EC2) instance directly accessible by the internet (even with ports restricted by security groups) without a load balancer, or [CloudFront](https://aws.amazon.com/cloudfront). This helps protect it from unintended access through an operating system or application issue. A subnet can also have a network ACL attached to it, which acts as a stateless firewall. You should configure the network ACL to narrow the scope of traffic allowed between layers, note that you need to define both inbound and outbound rules.
Some AWS services require components to access the internet for making API calls, where [AWS API endpoints](https://docs.aws.amazon.com/general/latest/gr/rande.html) are located. Other AWS services use [VPC endpoints](https://docs.aws.amazon.com/vpc/latest/privatelink/vpc-endpoints.html) within your Amazon VPCs. Many AWS services, including Amazon S3 and Amazon DynamoDB, support VPC endpoints, and this technology has been generalized in [AWS PrivateLink](https://aws.amazon.com/privatelink/). We recommend you use this approach to access AWS services, third-party services, and your own services hosted in other VPCs securely. All network traffic on AWS PrivateLink stays on the global AWS backbone and never traverses the internet. Connectivity can only be initiated by the consumer of the service, and not by the provider of the service. Using AWS PrivateLink for external service access allows you to create air-gapped VPCs with no internet access and helps protect your VPCs from external threat vectors. Third-party services can use AWS PrivateLink to allow their customers to connect to the services from their VPCs over private IP addresses. For VPC assets that need to make outbound connections to the internet, these can be made outbound only (one-way) through an AWS managed NAT gateway, outbound only internet gateway, or web proxies that you create and manage.
**Level of risk exposed if this best practice is not established:** High
## Implementation guidance
+ Control network traffic in a VPC: Implement VPC best practices to control traffic.
+ [Amazon VPC security](https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Security.html)
+ [VPC endpoints](https://docs.aws.amazon.com/vpc/latest/userguide/vpc-endpoints.html)
+ [Amazon VPC security group](https://docs.aws.amazon.com/vpc/latest/userguide/VPC_SecurityGroups.html)
+ [Network ACLs](https://docs.aws.amazon.com/vpc/latest/userguide/vpc-network-acls.html)
+ Control traffic at the edge: Implement edge services, such as Amazon CloudFront, to provide an additional layer of protection and other features.
+ [Amazon CloudFront use cases](https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/IntroductionUseCases.html)
+ [AWS Global Accelerator](https://docs.aws.amazon.com/global-accelerator/latest/dg/what-is-global-accelerator.html)
+ [AWS Web Application Firewall (AWS WAF)](https://docs.aws.amazon.com/waf/latest/developerguide/waf-section.html)
+ [Amazon Route 53](https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/Welcome.html)
+ [Amazon VPC Ingress Routing](https://aws.amazon.com/about-aws/whats-new/2019/12/amazon-vpc-ingress-routing-insert-virtual-appliances-forwarding-path-vpc-traffic/)
+ Control private network traffic: Implement services that protect your private traffic for your workload.
+ [Amazon VPC Peering](https://docs.aws.amazon.com/vpc/latest/peering/what-is-vpc-peering.html)
+ [Amazon VPC Endpoint Services (AWS PrivateLink)](https://docs.aws.amazon.com/vpc/latest/userguide/endpoint-service.html)
+ [Amazon VPC Transit Gateway](https://docs.aws.amazon.com/vpc/latest/tgw/what-is-transit-gateway.html)
+ [AWS Direct Connect](https://docs.aws.amazon.com/directconnect/latest/UserGuide/Welcome.html)
+ [AWS Site-to-Site VPN](https://docs.aws.amazon.com/vpn/latest/s2svpn/VPC_VPN.html)
+ [AWS Client VPN](https://docs.aws.amazon.com/vpn/latest/clientvpn-user/user-getting-started.html)
+ [Amazon S3 Access Points](https://docs.aws.amazon.com/AmazonS3/latest/dev/access-points.html)
## Resources
**Related documents:**
+ [AWS Firewall Manager](https://docs.aws.amazon.com/waf/latest/developerguide/fms-section.html)
+ [Amazon Inspector](https://aws.amazon.com/inspector)
+ [Getting started with AWS WAF](https://docs.aws.amazon.com/waf/latest/developerguide/getting-started.html)
**Related videos:**
+ [AWS Transit Gateway reference architectures for many VPCs](https://youtu.be/9Nikqn_02Oc)
+ [Application Acceleration and Protection with Amazon CloudFront, AWS WAF, and AWS Shield](https://youtu.be/0xlwLEccRe0)
**Related examples:**
+ [Lab: Automated Deployment of VPC](https://www.wellarchitectedlabs.com/Security/200_Automated_Deployment_of_VPC/README.html)
# SEC05-BP03 Automate network protection
Automate protection mechanisms to provide a self-defending network based on threat intelligence and anomaly detection. For example, intrusion detection and prevention tools that can adapt to current threats and reduce their impact. A web application firewall is an example of where you can automate network protection, for example, by using the AWS WAF Security Automations solution ([https://github.com/awslabs/aws-waf-security-automations](https://github.com/awslabs/aws-waf-security-automations)) to automatically block requests originating from IP addresses associated with known threat actors.
**Level of risk exposed if this best practice is not established:** Medium
## Implementation guidance
+ Automate protection for web-based traffic: AWS offers a solution that uses AWS CloudFormation to automatically deploy a set of AWS WAF rules designed to filter common web-based attacks. Users can select from preconfigured protective features that define the rules included in an AWS WAF web access control list (web ACL).
+ [AWS WAF security automations](https://aws.amazon.com/solutions/aws-waf-security-automations/)
+ Consider AWS Partner solutions: AWS Partners offer hundreds of industry-leading products that are equivalent, identical to, or integrate with existing controls in your on-premises environments. These products complement the existing AWS services to enable you to deploy a comprehensive security architecture and a more seamless experience across your cloud and on-premises environments.
+ [Infrastructure security](https://aws.amazon.com/security/partner-solutions/#infrastructure_security)
## Resources
**Related documents:**
+ [AWS Firewall Manager](https://docs.aws.amazon.com/waf/latest/developerguide/fms-section.html)
+ [Amazon Inspector](https://aws.amazon.com/inspector)
+ [Amazon VPC Security](https://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Security.html)
+ [Getting started with AWS WAF](https://docs.aws.amazon.com/waf/latest/developerguide/getting-started.html)
**Related videos:**
+ [AWS Transit Gateway reference architectures for many VPCs](https://youtu.be/9Nikqn_02Oc)
+ [Application Acceleration and Protection with Amazon CloudFront, AWS WAF, and AWS Shield](https://youtu.be/0xlwLEccRe0)
**Related examples:**
+ [Lab: Automated Deployment of VPC](https://www.wellarchitectedlabs.com/Security/200_Automated_Deployment_of_VPC/README.html)
# SEC05-BP04 Implement inspection and protection
Inspect and filter your traffic at each layer. You can inspect your VPC configurations for potential unintended access using [VPC Network Access Analyzer](https://docs.aws.amazon.com/vpc/latest/network-access-analyzer/what-is-vaa.html). You can specify your network access requirements and identify potential network paths that do not meet them. For components transacting over HTTP-based protocols, a web application firewall can help protect from common attacks. [AWS WAF](https://aws.amazon.com/waf) is a web application firewall that lets you monitor and block HTTP(s) requests that match your configurable rules that are forwarded to an Amazon API Gateway API, Amazon CloudFront, or an Application Load Balancer. To get started with AWS WAF, you can use [AWS Managed Rules](https://docs.aws.amazon.com/waf/latest/developerguide/getting-started.html#getting-started-wizard-add-rule-group) in combination with your own, or use existing [partner integrations](https://aws.amazon.com/waf/partners/).
For managing AWS WAF, AWS Shield Advanced protections, and Amazon VPC security groups across AWS Organizations, you can use AWS Firewall Manager. It allows you to centrally configure and manage firewall rules across your accounts and applications, making it easier to scale enforcement of common rules. It also enables you to rapidly respond to attacks, using [AWS Shield Advanced](https://docs.aws.amazon.com/waf/latest/developerguide/ddos-responding.html), or [solutions](https://aws.amazon.com/solutions/aws-waf-security-automations/) that can automatically block unwanted requests to your web applications. Firewall Manager also works with [AWS Network Firewall](https://aws.amazon.com/network-firewall/). AWS Network Firewall is a managed service that uses a rules engine to give you fine-grained control over both stateful and stateless network traffic. It supports the [Suricata compatible](https://docs.aws.amazon.com/network-firewall/latest/developerguide/stateful-rule-groups-ips.html) open source intrusion prevention system (IPS) specifications for rules to help protect your workload.
**Level of risk exposed if this best practice is not established:** Low
## Implementation guidance
+ Configure Amazon GuardDuty: GuardDuty is a threat detection service that continuously monitors for malicious activity and unauthorized behavior to protect your AWS accounts and workloads. Enable GuardDuty and configure automated alerts.
+ [Amazon GuardDuty](https://docs.aws.amazon.com/guardduty/latest/ug/what-is-guardduty.html)
+ [Lab: Automated Deployment of Detective Controls](https://wellarchitectedlabs.com/Security/200_Automated_Deployment_of_Detective_Controls/README.html)
+ Configure virtual private cloud (VPC) Flow Logs: VPC Flow Logs is a feature that enables you to capture information about the IP traffic going to and from network interfaces in your VPC. Flow log data can be published to Amazon CloudWatch Logs and Amazon Simple Storage Service (Amazon S3). After you've created a flow log, you can retrieve and view its data in the chosen destination.
+ Consider VPC traffic mirroring: Traffic mirroring is an Amazon VPC feature that you can use to copy network traffic from an elastic network interface of Amazon Elastic Compute Cloud (Amazon EC2) instances and then send it to out-of-band security and monitoring appliances for content inspection, threat monitoring, and troubleshooting.
+ [VPC traffic mirroring](https://docs.aws.amazon.com/vpc/latest/mirroring/what-is-traffic-mirroring.html)
## Resources
**Related documents:**
+ [AWS Firewall Manager](https://docs.aws.amazon.com/waf/latest/developerguide/fms-section.html)
+ [Amazon Inspector](https://aws.amazon.com/inspector)
+ [Amazon VPC Security](https://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Security.html)
+ [Getting started with AWS WAF](https://docs.aws.amazon.com/waf/latest/developerguide/getting-started.html)
**Related videos:**
+ [AWS Transit Gateway reference architectures for many VPCs](https://youtu.be/9Nikqn_02Oc)
+ [Application Acceleration and Protection with Amazon CloudFront, AWS WAF, and AWS Shield](https://youtu.be/0xlwLEccRe0)
**Related examples:**
+ [Lab: Automated Deployment of VPC](https://www.wellarchitectedlabs.com/Security/200_Automated_Deployment_of_VPC/README.html)