network-firewall

This component is responsible for provisioning AWS Network Firewall resources, including Network Firewall, firewall policy, rule groups, and logging configuration.

Usage

Stack Level: Regional

Example of a Network Firewall with stateful 5-tuple rules:

tip

The "5-tuple" means the five items (columns) that each rule (row, or tuple) in a firewall policy uses to define whether to block or allow traffic: source and destination IP, source and destination port, and protocol.

Refer to Standard stateful rule groups in AWS Network Firewall for more details.

components:
  terraform:
    network-firewall:
      settings:
        spacelift:
          workspace_enabled: true
      vars:
        enabled: true
        name: network-firewall
        # The name of a VPC component where the Network Firewall is provisioned
        vpc_component_name: vpc
        firewall_subnet_name: "firewall"
        stateful_default_actions:
          - "aws:alert_strict"
        stateless_default_actions:
          - "aws:forward_to_sfe"
        stateless_fragment_default_actions:
          - "aws:forward_to_sfe"
        stateless_custom_actions: []
        delete_protection: false
        firewall_policy_change_protection: false
        subnet_change_protection: false
        logging_config: []
        rule_group_config:
          stateful-packet-inspection:
            capacity: 50
            name: stateful-packet-inspection
            description: "Stateful inspection of packets"
            type: "STATEFUL"
            rule_group:
              stateful_rule_options:
                rule_order: "STRICT_ORDER"
              rules_source:
                stateful_rule:
                  - action: "DROP"
                    header:
                      destination: "124.1.1.24/32"
                      destination_port: 53
                      direction: "ANY"
                      protocol: "TCP"
                      source: "1.2.3.4/32"
                      source_port: 53
                    rule_option:
                      keyword: "sid:1"
                  - action: "PASS"
                    header:
                      destination: "ANY"
                      destination_port: "ANY"
                      direction: "ANY"
                      protocol: "TCP"
                      source: "10.10.192.0/19"
                      source_port: "ANY"
                    rule_option:
                      keyword: "sid:2"
                  - action: "PASS"
                    header:
                      destination: "ANY"
                      destination_port: "ANY"
                      direction: "ANY"
                      protocol: "TCP"
                      source: "10.10.224.0/19"
                      source_port: "ANY"
                    rule_option:
                      keyword: "sid:3"

Example of a Network Firewall with Suricata rules:

tip

For Suricata rule group type, you provide match and action settings in a string, in a Suricata compatible specification. The specification fully defines what the stateful rules engine looks for in a traffic flow and the action to take on the packets in a flow that matches the inspection criteria.

Refer to Suricata compatible rule strings in AWS Network Firewall for more details.

components:
  terraform:
    network-firewall:
      metadata:
        component: "network-firewall"
      settings:
        spacelift:
          workspace_enabled: true
      vars:
        enabled: true
        name: "network-firewall"

        # The name of a VPC component where the Network Firewall is provisioned
        vpc_component_name: "vpc"
        firewall_subnet_name: "firewall"

        delete_protection: false
        firewall_policy_change_protection: false
        subnet_change_protection: false

        # Logging config
        logging_enabled: true
        flow_logs_bucket_component_name: "network-firewall-logs-bucket-flow"
        alert_logs_bucket_component_name: "network-firewall-logs-bucket-alert"

        # https://docs.aws.amazon.com/network-firewall/latest/developerguide/stateless-default-actions.html
        # https://docs.aws.amazon.com/network-firewall/latest/APIReference/API_FirewallPolicy.html
        # https://docs.aws.amazon.com/network-firewall/latest/developerguide/rule-action.html#rule-action-stateless
        stateless_default_actions:
          - "aws:forward_to_sfe"
        stateless_fragment_default_actions:
          - "aws:forward_to_sfe"
        stateless_custom_actions: []

        # https://docs.aws.amazon.com/network-firewall/latest/developerguide/suricata-rule-evaluation-order.html#suricata-strict-rule-evaluation-order.html
        # https://github.com/aws-samples/aws-network-firewall-strict-rule-ordering-terraform
        policy_stateful_engine_options_rule_order: "STRICT_ORDER"

        # https://docs.aws.amazon.com/network-firewall/latest/developerguide/stateful-default-actions.html
        # https://docs.aws.amazon.com/network-firewall/latest/developerguide/suricata-rule-evaluation-order.html#suricata-default-rule-evaluation-order
        # https://docs.aws.amazon.com/network-firewall/latest/APIReference/API_FirewallPolicy.html
        stateful_default_actions:
          - "aws:alert_established"
        #  - "aws:alert_strict"
        #  - "aws:drop_established"
        #  - "aws:drop_strict"

        # https://docs.aws.amazon.com/network-firewall/latest/developerguide/rule-groups.html
        rule_group_config:
          stateful-inspection:
            # https://docs.aws.amazon.com/network-firewall/latest/developerguide/rule-group-managing.html#nwfw-rule-group-capacity
            # For stateful rules, `capacity` means the max number of rules in the rule group
            capacity: 1000
            name: "stateful-inspection"
            description: "Stateful inspection of packets"
            type: "STATEFUL"

            rule_group:
              rule_variables:
                port_sets: []
                ip_sets:
                  - key: "CIDR_1"
                    definition:
                      - "10.10.0.0/11"
                  - key: "CIDR_2"
                    definition:
                      - "10.11.0.0/11"
                  - key: "SCANNER"
                    definition:
                      - "10.12.48.186/32"
                  # bad actors
                  - key: "BLOCKED_LIST"
                    definition:
                      - "193.142.146.35/32"
                      - "69.40.195.236/32"
                      - "125.17.153.207/32"
                      - "185.220.101.4/32"
                      - "195.219.212.151/32"
                      - "162.247.72.199/32"
                      - "147.185.254.17/32"
                      - "179.60.147.101/32"
                      - "157.230.244.66/32"
                      - "192.99.4.116/32"
                      - "62.102.148.69/32"
                      - "185.129.62.62/32"

              stateful_rule_options:
                # https://docs.aws.amazon.com/network-firewall/latest/developerguide/suricata-rule-evaluation-order.html#suricata-strict-rule-evaluation-order.html
                # All the stateful rule groups are provided to the rule engine as Suricata compatible strings
                # Suricata can evaluate stateful rule groups by using the default rule group ordering method,
                # or you can set an exact order using the strict ordering method.
                # The settings for your rule groups must match the settings for the firewall policy that they belong to.
                # With strict ordering, the rule groups are evaluated by order of priority, starting from the lowest number,
                # and the rules in each rule group are processed in the order in which they're defined.
                rule_order: "STRICT_ORDER"

              # https://docs.aws.amazon.com/network-firewall/latest/developerguide/suricata-how-to-provide-rules.html
              rules_source:
                # Suricata rules for the rule group
                # https://docs.aws.amazon.com/network-firewall/latest/developerguide/suricata-examples.html
                # https://docs.aws.amazon.com/network-firewall/latest/developerguide/suricata-rule-evaluation-order.html
                # https://github.com/aws-samples/aws-network-firewall-terraform/blob/main/firewall.tf#L66
                # https://docs.aws.amazon.com/network-firewall/latest/developerguide/stateful-rule-groups-suricata.html
                # https://coralogix.com/blog/writing-effective-suricata-rules-for-the-sta/
                # https://suricata.readthedocs.io/en/suricata-6.0.10/rules/intro.html
                # https://suricata.readthedocs.io/en/suricata-6.0.0/rules/header-keywords.html
                # https://docs.aws.amazon.com/network-firewall/latest/developerguide/rule-action.html
                #
                # With Strict evaluation order, the rules in each rule group are processed in the order in which they're defined
                #
                # Pass – Discontinue inspection of the matching packet and permit it to go to its intended destination
                #
                # Drop or Alert – Evaluate the packet against all rules with drop or alert action settings.
                # If the firewall has alert logging configured, send a message to the firewall's alert logs for each matching rule.
                # The first log entry for the packet will be for the first rule that matched the packet.
                # After all rules have been evaluated, handle the packet according to the action setting in the first rule that matched the packet.
                # If the first rule has a drop action, block the packet. If it has an alert action, continue evaluation.
                #
                # Reject – Drop traffic that matches the conditions of the stateful rule and send a TCP reset packet back to sender of the packet.
                # A TCP reset packet is a packet with no payload and a RST bit contained in the TCP header flags.
                # Reject is available only for TCP traffic. This option doesn't support FTP and IMAP protocols.
                rules_string: |
                  alert ip $BLOCKED_LIST any <> any any ( msg:"Alert on blocked traffic"; sid:100; rev:1; )
                  drop ip $BLOCKED_LIST any <> any any ( msg:"Blocked blocked traffic"; sid:200; rev:1; )

                  pass ip $SCANNER any -> any any ( msg: "Allow scanner"; sid:300; rev:1; )

                  alert ip $CIDR_1 any -> $CIDR_2 any ( msg:"Alert on CIDR_1 to CIDR_2 traffic"; sid:400; rev:1; )
                  drop ip $CIDR_1 any -> $CIDR_2 any ( msg:"Blocked CIDR_1 to CIDR_2 traffic"; sid:410; rev:1; )

                  pass ip any any <> any any ( msg: "Allow general traffic"; sid:10000; rev:1; )

Variables

Required Variables

region (string) required

AWS Region

rule_group_config (any) required

Rule group configuration. Refer to networkfirewall_rule_group for configuration details

vpc_component_name (string) required

The name of a VPC component where the Network Firewall is provisioned

Optional Variables

alert_logs_bucket_component_name (string) optional

Alert logs bucket component name

Default value: null

delete_protection (bool) optional

A boolean flag indicating whether it is possible to delete the firewall

Default value: false

firewall_policy_change_protection (bool) optional

A boolean flag indicating whether it is possible to change the associated firewall policy

Default value: false

firewall_subnet_name (string) optional

Firewall subnet name

Default value: "firewall"

flow_logs_bucket_component_name (string) optional

Flow logs bucket component name

Default value: null

logging_enabled (bool) optional

Flag to enable/disable Network Firewall Flow and Alert Logs

Default value: false

network_firewall_description (string) optional

AWS Network Firewall description. If not provided, the Network Firewall name will be used

Default value: null

network_firewall_name (string) optional

Friendly name to give the Network Firewall. If not provided, the name will be derived from the context.
Changing the name will cause the Firewall to be deleted and recreated.

Default value: null

network_firewall_policy_name (string) optional

Friendly name to give the Network Firewall policy. If not provided, the name will be derived from the context.
Changing the name will cause the policy to be deleted and recreated.

Default value: null

policy_stateful_engine_options_rule_order (string) optional

Indicates how to manage the order of stateful rule evaluation for the policy. Valid values: DEFAULT_ACTION_ORDER, STRICT_ORDER

Default value: null

stateful_default_actions (list(string)) optional

Default stateful actions

Default value:

[
  "aws:alert_strict"
]

stateless_custom_actions optional

Set of configuration blocks describing the custom action definitions that are available for use in the firewall policy's stateless_default_actions

Type:

list(object({
action_name = string
dimensions  = list(string)
}))

Default value: [ ]

stateless_default_actions (list(string)) optional

Default stateless actions

Default value:

[
  "aws:forward_to_sfe"
]

stateless_fragment_default_actions (list(string)) optional

Default stateless actions for fragmented packets

Default value:

[
  "aws:forward_to_sfe"
]

subnet_change_protection (bool) optional

A boolean flag indicating whether it is possible to change the associated subnet(s)

Default value: false

Context Variables

The following variables are defined in the context.tf file of this module and part of the terraform-null-label pattern.

additional_tag_map (map(string)) optional

Additional key-value pairs to add to each map in tags_as_list_of_maps. Not added to tags or id.
This is for some rare cases where resources want additional configuration of tags
and therefore take a list of maps with tag key, value, and additional configuration.

Required: No

Default value: { }

attributes (list(string)) optional

ID element. Additional attributes (e.g. workers or cluster) to add to id,
in the order they appear in the list. New attributes are appended to the
end of the list. The elements of the list are joined by the delimiter
and treated as a single ID element.

Required: No

Default value: [ ]

context (any) optional

Single object for setting entire context at once.
See description of individual variables for details.
Leave string and numeric variables as null to use default value.
Individual variable settings (non-null) override settings in context object,
except for attributes, tags, and additional_tag_map, which are merged.

Required: No

Default value:

{
  "additional_tag_map": {},
  "attributes": [],
  "delimiter": null,
  "descriptor_formats": {},
  "enabled": true,
  "environment": null,
  "id_length_limit": null,
  "label_key_case": null,
  "label_order": [],
  "label_value_case": null,
  "labels_as_tags": [
    "unset"
  ],
  "name": null,
  "namespace": null,
  "regex_replace_chars": null,
  "stage": null,
  "tags": {},
  "tenant": null
}

delimiter (string) optional

Delimiter to be used between ID elements.
Defaults to - (hyphen). Set to "" to use no delimiter at all.

Required: No

Default value: null

descriptor_formats (any) optional

Describe additional descriptors to be output in the descriptors output map.
Map of maps. Keys are names of descriptors. Values are maps of the form
\{<br/> format = string<br/> labels = list(string)<br/> \}
(Type is any so the map values can later be enhanced to provide additional options.)
format is a Terraform format string to be passed to the format() function.
labels is a list of labels, in order, to pass to format() function.
Label values will be normalized before being passed to format() so they will be
identical to how they appear in id.
Default is {} (descriptors output will be empty).

Required: No

Default value: { }

enabled (bool) optional

Set to false to prevent the module from creating any resources
Required: No

Default value: null

environment (string) optional

ID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT'
Required: No

Default value: null

id_length_limit (number) optional

Limit id to this many characters (minimum 6).
Set to 0 for unlimited length.
Set to null for keep the existing setting, which defaults to 0.
Does not affect id_full.

Required: No

Default value: null

label_key_case (string) optional

Controls the letter case of the tags keys (label names) for tags generated by this module.
Does not affect keys of tags passed in via the tags input.
Possible values: lower, title, upper.
Default value: title.

Required: No

Default value: null

label_order (list(string)) optional

The order in which the labels (ID elements) appear in the id.
Defaults to ["namespace", "environment", "stage", "name", "attributes"].
You can omit any of the 6 labels ("tenant" is the 6th), but at least one must be present.

Required: No

Default value: null

label_value_case (string) optional

Controls the letter case of ID elements (labels) as included in id,
set as tag values, and output by this module individually.
Does not affect values of tags passed in via the tags input.
Possible values: lower, title, upper and none (no transformation).
Set this to title and set delimiter to "" to yield Pascal Case IDs.
Default value: lower.

Required: No

Default value: null

labels_as_tags (set(string)) optional

Set of labels (ID elements) to include as tags in the tags output.
Default is to include all labels.
Tags with empty values will not be included in the tags output.
Set to [] to suppress all generated tags.
Notes:
The value of the name tag, if included, will be the id, not the name.
Unlike other null-label inputs, the initial setting of labels_as_tags cannot be
changed in later chained modules. Attempts to change it will be silently ignored.

Required: No

Default value:

[
  "default"
]

name (string) optional

ID element. Usually the component or solution name, e.g. 'app' or 'jenkins'.
This is the only ID element not also included as a tag.
The "name" tag is set to the full id string. There is no tag with the value of the name input.

Required: No

Default value: null

namespace (string) optional

ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique
Required: No

Default value: null

regex_replace_chars (string) optional

Terraform regular expression (regex) string.
Characters matching the regex will be removed from the ID elements.
If not set, "/[^a-zA-Z0-9-]/" is used to remove all characters other than hyphens, letters and digits.

Required: No

Default value: null

stage (string) optional

ID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release'
Required: No

Default value: null

tags (map(string)) optional

Additional tags (e.g. {'BusinessUnit': 'XYZ'}).
Neither the tag keys nor the tag values will be modified by this module.

Required: No

Default value: { }

tenant (string) optional

ID element (Rarely used, not included by default). A customer identifier, indicating who this instance of a resource is for
Required: No

Default value: null

Outputs

az_subnet_endpoint_stats

List of objects with each object having three items: AZ, subnet ID, VPC endpoint ID

network_firewall_arn

Network Firewall ARN

network_firewall_name

Network Firewall name

network_firewall_policy_arn

Network Firewall policy ARN

network_firewall_policy_name

Network Firewall policy name

network_firewall_status

Nested list of information about the current status of the Network Firewall

Dependencies

Requirements

• terraform, version: >= 1.0.0
• aws, version: >= 4.9.0

Modules

Name	Version	Source	Description
alert_logs_bucket	1.5.0	cloudposse/stack-config/yaml//modules/remote-state	n/a
flow_logs_bucket	1.5.0	cloudposse/stack-config/yaml//modules/remote-state	n/a
iam_roles	latest	../account-map/modules/iam-roles	n/a
network_firewall	0.3.2	cloudposse/network-firewall/aws	n/a
this	0.25.0	cloudposse/label/null	n/a
vpc	1.5.0	cloudposse/stack-config/yaml//modules/remote-state	n/a

References

• Deploy centralized traffic filtering using AWS Network Firewall
• AWS Network Firewall – New Managed Firewall Service in VPC
• Deployment models for AWS Network Firewall
• Deployment models for AWS Network Firewall with VPC routing enhancements
• Inspection Deployment Models with AWS Network Firewall
• How to deploy AWS Network Firewall by using AWS Firewall Manager
• A Deep Dive into AWS Transit Gateway
• Appliance in a shared services VPC
• cloudposse/terraform-aws-components - Cloud Posse's upstream component