Note
This is the latest version of AWS WAF , named AWS WAFV2, released in November, 2019. For information, including how to migrate your AWS WAF resources from the prior release, see the AWS WAF developer guide.
Use an AWS::WAFv2::WebACL to define a collection of rules to use to inspect and control web requests. Each rule in a web ACL has a statement that defines what to look for in web requests and an action that AWS WAF applies to requests that match the statement. In the web ACL, you assign a default action to take (allow, block) for any request that doesn't match any of the rules.
The rules in a web ACL can be a combination of explicitly defined rules and rule groups that you reference from the web ACL. The rule groups can be rule groups that you manage or rule groups that are managed by others.
You can associate a web ACL with one or more AWS resources to protect. The resources can be an Amazon CloudFront distribution, an Amazon API Gateway REST API, an Application Load Balancer, an AWS AppSync GraphQL API , an Amazon Cognito user pool, an AWS App Runner service, or an AWS Verified Access instance.
For more information, see Web access control lists (web ACLs) in the AWS WAF developer guide.
Web ACLs used in AWS Shield Advanced automatic application layer DDoS mitigation
If you use Shield Advanced automatic application layer DDoS mitigation, the web ACLs that you use
with automatic mitigation have a rule group rule whose name starts with ShieldMitigationRuleGroup. This rule is
used for automatic mitigations and it's managed for you in the web ACL by Shield Advanced and AWS WAF.
You'll see the rule listed among the web ACL rules when you view the web ACL through the AWS WAF interfaces.
When you manage the web ACL through AWS CloudFormation interfaces, you won't see the Shield Advanced rule. AWS CloudFormation doesn't include this type of rule in the stack drift status between the actual configuration of the web ACL and your web ACL template.
Don't add the Shield Advanced rule group rule to your web ACL template. The rule shouldn't be in your template. When you update the web ACL template in a stack, the Shield Advanced rule is maintained for you by AWS WAF in the resulting web ACL.
For more information, see Shield Advanced automatic application layer DDoS mitigation in the AWS Shield Advanced developer guide.
Syntax
To declare this entity in your AWS CloudFormation template, use the following syntax:
JSON
{
"Type" : "AWS::WAFv2::WebACL",
"Properties" : {
"AssociationConfig" : AssociationConfig,
"CaptchaConfig" : CaptchaConfig,
"ChallengeConfig" : ChallengeConfig,
"CustomResponseBodies" : {Key: Value, ...},
"DefaultAction" : DefaultAction,
"Description" : String,
"Name" : String,
"Rules" : [ Rule, ... ],
"Scope" : String,
"Tags" : [ Tag, ... ],
"TokenDomains" : [ String, ... ],
"VisibilityConfig" : VisibilityConfig
}
}
YAML
Type: AWS::WAFv2::WebACL
Properties:
AssociationConfig:
AssociationConfig
CaptchaConfig:
CaptchaConfig
ChallengeConfig:
ChallengeConfig
CustomResponseBodies:
Key: Value
DefaultAction:
DefaultAction
Description: String
Name: String
Rules:
- Rule
Scope: String
Tags:
- Tag
TokenDomains:
- String
VisibilityConfig:
VisibilityConfig
Properties
AssociationConfig-
Specifies custom configurations for the associations between the web ACL and protected resources.
Use this to customize the maximum size of the request body that your protected resources forward to AWS WAF for inspection. You can customize this setting for CloudFront, API Gateway, Amazon Cognito, App Runner, or Verified Access resources. The default setting is 16 KB (16,384 bytes).
Note
You are charged additional fees when your protected resources forward body sizes that are larger than the default. For more information, see AWS WAF Pricing
. For Application Load Balancer and AWS AppSync, the limit is fixed at 8 KB (8,192 bytes).
Required: No
Type: AssociationConfig
Update requires: No interruption
CaptchaConfig-
Specifies how AWS WAF should handle
CAPTCHAevaluations for rules that don't have their ownCaptchaConfigsettings. If you don't specify this, AWS WAF uses its default settings forCaptchaConfig.Required: No
Type: CaptchaConfig
Update requires: No interruption
ChallengeConfig-
Specifies how AWS WAF should handle challenge evaluations for rules that don't have their own
ChallengeConfigsettings. If you don't specify this, AWS WAF uses its default settings forChallengeConfig.Required: No
Type: ChallengeConfig
Update requires: No interruption
CustomResponseBodies-
A map of custom response keys and content bodies. When you create a rule with a block action, you can send a custom response to the web request. You define these for the web ACL, and then use them in the rules and default actions that you define in the web ACL.
For information about customizing web requests and responses, see Customizing web requests and responses in AWS WAF in the AWS WAF Developer Guide.
For information about the limits on count and size for custom request and response settings, see AWS WAF quotas in the AWS WAF Developer Guide.
Required: No
Type: Object of CustomResponseBody
Update requires: No interruption
DefaultAction-
The action to perform if none of the
Rulescontained in theWebACLmatch.Required: Yes
Type: DefaultAction
Update requires: No interruption
Description-
A description of the web ACL that helps with identification.
Required: No
Type: String
Pattern:
^[a-zA-Z0-9=:#@/\-,.][a-zA-Z0-9+=:#@/\-,.\s]+[a-zA-Z0-9+=:#@/\-,.]{1,256}$Update requires: No interruption
Name-
The name of the web ACL. You cannot change the name of a web ACL after you create it.
Required: No
Type: String
Pattern:
^[0-9A-Za-z_-]{1,128}$Update requires: Replacement
Rules-
The rule statements used to identify the web requests that you want to manage. Each rule includes one top-level statement that AWS WAF uses to identify matching web requests, and parameters that govern how AWS WAF handles them.
Required: No
Type: Array of Rule
Update requires: No interruption
Scope-
Specifies whether this is for an Amazon CloudFront distribution or for a regional application. A regional application can be an Application Load Balancer (ALB), an Amazon API Gateway REST API, an AWS AppSync GraphQL API, an Amazon Cognito user pool, an AWS App Runner service, or an AWS Verified Access instance. Valid Values are
CLOUDFRONTandREGIONAL.Note
For
CLOUDFRONT, you must create your WAFv2 resources in the US East (N. Virginia) Region,us-east-1.For information about how to define the association of the web ACL with your resource, see AWS::WAFv2::WebACLAssociation.
Required: Yes
Type: String
Allowed values:
CLOUDFRONT | REGIONALUpdate requires: Replacement
-
Key:value pairs associated with an AWS resource. The key:value pair can be anything you define. Typically, the tag key represents a category (such as "environment") and the tag value represents a specific value within that category (such as "test," "development," or "production"). You can add up to 50 tags to each AWS resource.
Note
To modify tags on existing resources, use the AWS WAF APIs or command line interface. With AWS CloudFormation, you can only add tags to AWS WAF resources during resource creation.
Required: No
Type: Array of Tag
Minimum:
1Update requires: No interruption
TokenDomains-
Specifies the domains that AWS WAF should accept in a web request token. This enables the use of tokens across multiple protected websites. When AWS WAF provides a token, it uses the domain of the AWS resource that the web ACL is protecting. If you don't specify a list of token domains, AWS WAF accepts tokens only for the domain of the protected resource. With a token domain list, AWS WAF accepts the resource's host domain plus all domains in the token domain list, including their prefixed subdomains.
Required: No
Type: Array of String
Minimum:
1Maximum:
253Update requires: No interruption
VisibilityConfig-
Defines and enables Amazon CloudWatch metrics and web request sample collection.
Required: Yes
Type: VisibilityConfig
Update requires: No interruption
Return values
Ref
The Ref for the resource, containing the resource name, physical ID, and scope, formatted as follows: name|id|scope.
For example: my-webacl-name|1234a1a-a1b1-12a1-abcd-a123b123456|REGIONAL.
Fn::GetAtt
The Fn::GetAtt intrinsic function returns a value for a specified attribute of this type. The following are the available attributes and sample return values.
For more information about using the Fn::GetAtt intrinsic function, see Fn::GetAtt.
Arn-
The Amazon Resource Name (ARN) of the web ACL.
Capacity-
The web ACL capacity units (WCUs) currently being used by this web ACL.
AWS WAF uses WCUs to calculate and control the operating resources that are used to run your rules, rule groups, and web ACLs. AWS WAF calculates capacity differently for each rule type, to reflect the relative cost of each rule. Simple rules that cost little to run use fewer WCUs than more complex rules that use more processing power. Rule group capacity is fixed at creation, which helps users plan their web ACL WCU usage when they use a rule group. The WCU limit for web ACLs is 1,500.
Id-
The ID of the web ACL.
LabelNamespace-
The label namespace prefix for this web ACL. All labels added by rules in this web ACL have this prefix.
The syntax for the label namespace prefix for a web ACL is the following:
awswaf:<account ID>:webacl:<web ACL name>:When a rule with a label matches a web request, AWS WAF adds the fully qualified label to the request. A fully qualified label is made up of the label namespace from the rule group or web ACL where the rule is defined and the label from the rule, separated by a colon.
Examples
Create a web ACL with a variety of rate-based rules
The following example web ACL specification shows a number of rate-based rules. For information about each rule, see the
examples under AWS::WAFv2::WebACL RateBasedStatement.
YAML
Name: exampleWebACL
Id: exampleWebACLExampleID
ARN: arn:aws:wafv2:us-east-1:ExampleAccountNumber:regional/webacl/exampleWebACL/exampleWebACLExampleID
DefaultAction:
Allow: {}
Description: ''
Rules:
- Name: rbrCountAll
Priority: 0
Statement:
RateBasedStatement:
Limit: 100000
AggregateKeyType: CONSTANT
ScopeDownStatement:
GeoMatchStatement:
CountryCodes:
- GB
ForwardedIPConfig:
HeaderName: X-Forwarded-For
FallbackBehavior: MATCH
Action:
Block: {}
VisibilityConfig:
SampledRequestsEnabled: true
CloudWatchMetricsEnabled: true
MetricName: rbrCountAll
- Name: rbrNoCustomKeys
Priority: 1
Statement:
RateBasedStatement:
Limit: 1000
AggregateKeyType: FORWARDED_IP
ForwardedIPConfig:
HeaderName: X-Forwarded-For
FallbackBehavior: MATCH
Action:
Block: {}
VisibilityConfig:
SampledRequestsEnabled: true
CloudWatchMetricsEnabled: true
MetricName: rbrNoCustomKeys
- Name: rbrCustomKeysA
Priority: 2
Statement:
RateBasedStatement:
Limit: 2000
AggregateKeyType: CUSTOM_KEYS
ForwardedIPConfig:
HeaderName: X-Forwarded-For
FallbackBehavior: MATCH
CustomKeys:
- Header:
Name: Content-Type
TextTransformations:
- Priority: 0
Type: NONE
- ForwardedIP: {}
Action:
Block: {}
VisibilityConfig:
SampledRequestsEnabled: true
CloudWatchMetricsEnabled: true
MetricName: rbrCustomKeysA
- Name: rbrCustomKeysB
Priority: 3
Statement:
RateBasedStatement:
Limit: 3000
AggregateKeyType: CUSTOM_KEYS
CustomKeys:
- QueryString:
TextTransformations:
- Priority: 0
Type: NONE
- HTTPMethod: {}
- UriPath:
TextTransformations:
- Priority: 0
Type: NONE
Action:
Block: {}
VisibilityConfig:
SampledRequestsEnabled: true
CloudWatchMetricsEnabled: true
MetricName: rbrCustomKeysB
- Name: labelUSStates
Priority: 4
Statement:
GeoMatchStatement:
CountryCodes:
- US
Action:
Count: {}
VisibilityConfig:
SampledRequestsEnabled: true
CloudWatchMetricsEnabled: true
MetricName: labelUSStates
- Name: rbrRequestsFromUSStates
Priority: 5
Statement:
RateBasedStatement:
Limit: 500
AggregateKeyType: CUSTOM_KEYS
ScopeDownStatement:
GeoMatchStatement:
CountryCodes:
- US
CustomKeys:
- LabelNamespace:
Namespace: 'awswaf:clientip:geo:region:'
Action:
Block: {}
VisibilityConfig:
SampledRequestsEnabled: true
CloudWatchMetricsEnabled: true
MetricName: rbrRequestsFromUSStates
VisibilityConfig:
SampledRequestsEnabled: true
CloudWatchMetricsEnabled: true
MetricName: exampleWebACL
Capacity: 193
ManagedByFirewallManager: false
LabelNamespace: 'awswaf:ExampleAccountNumber:webacl:exampleWebACL:' JSON
{
"Name": "exampleWebACL",
"Id": "exampleWebACLExampleID",
"ARN": "arn:aws:wafv2:us-east-1:ExampleAccountNumber:regional/webacl/exampleWebACL/exampleWebACLExampleID",
"DefaultAction": {
"Allow": {}
},
"Description": "",
"Rules": [
{
"Name": "rbrCountAll",
"Priority": 0,
"Statement": {
"RateBasedStatement": {
"Limit": 100000,
"AggregateKeyType": "CONSTANT",
"ScopeDownStatement": {
"GeoMatchStatement": {
"CountryCodes": [
"GB"
],
"ForwardedIPConfig": {
"HeaderName": "X-Forwarded-For",
"FallbackBehavior": "MATCH"
}
}
}
}
},
"Action": {
"Block": {}
},
"VisibilityConfig": {
"SampledRequestsEnabled": true,
"CloudWatchMetricsEnabled": true,
"MetricName": "rbrCountAll"
}
},
{
"Name": "rbrNoCustomKeys",
"Priority": 1,
"Statement": {
"RateBasedStatement": {
"Limit": 1000,
"AggregateKeyType": "FORWARDED_IP",
"ForwardedIPConfig": {
"HeaderName": "X-Forwarded-For",
"FallbackBehavior": "MATCH"
}
}
},
"Action": {
"Block": {}
},
"VisibilityConfig": {
"SampledRequestsEnabled": true,
"CloudWatchMetricsEnabled": true,
"MetricName": "rbrNoCustomKeys"
}
},
{
"Name": "rbrCustomKeysA",
"Priority": 2,
"Statement": {
"RateBasedStatement": {
"Limit": 2000,
"AggregateKeyType": "CUSTOM_KEYS",
"ForwardedIPConfig": {
"HeaderName": "X-Forwarded-For",
"FallbackBehavior": "MATCH"
},
"CustomKeys": [
{
"Header": {
"Name": "Content-Type",
"TextTransformations": [
{
"Priority": 0,
"Type": "NONE"
}
]
}
},
{
"ForwardedIP": {}
}
]
}
},
"Action": {
"Block": {}
},
"VisibilityConfig": {
"SampledRequestsEnabled": true,
"CloudWatchMetricsEnabled": true,
"MetricName": "rbrCustomKeysA"
}
},
{
"Name": "rbrCustomKeysB",
"Priority": 3,
"Statement": {
"RateBasedStatement": {
"Limit": 3000,
"AggregateKeyType": "CUSTOM_KEYS",
"CustomKeys": [
{
"QueryString": {
"TextTransformations": [
{
"Priority": 0,
"Type": "NONE"
}
]
}
},
{
"HTTPMethod": {}
},
{
"UriPath": {
"TextTransformations": [
{
"Priority": 0,
"Type": "NONE"
}
]
}
}
]
}
},
"Action": {
"Block": {}
},
"VisibilityConfig": {
"SampledRequestsEnabled": true,
"CloudWatchMetricsEnabled": true,
"MetricName": "rbrCustomKeysB"
}
},
{
"Name": "labelUSStates",
"Priority": 4,
"Statement": {
"GeoMatchStatement": {
"CountryCodes": [
"US"
]
}
},
"Action": {
"Count": {}
},
"VisibilityConfig": {
"SampledRequestsEnabled": true,
"CloudWatchMetricsEnabled": true,
"MetricName": "labelUSStates"
}
},
{
"Name": "rbrRequestsFromUSStates",
"Priority": 5,
"Statement": {
"RateBasedStatement": {
"Limit": 500,
"AggregateKeyType": "CUSTOM_KEYS",
"ScopeDownStatement": {
"GeoMatchStatement": {
"CountryCodes": [
"US"
]
}
},
"CustomKeys": [
{
"LabelNamespace": {
"Namespace": "awswaf:clientip:geo:region:"
}
}
]
}
},
"Action": {
"Block": {}
},
"VisibilityConfig": {
"SampledRequestsEnabled": true,
"CloudWatchMetricsEnabled": true,
"MetricName": "rbrRequestsFromUSStates"
}
}
],
"VisibilityConfig": {
"SampledRequestsEnabled": true,
"CloudWatchMetricsEnabled": true,
"MetricName": "exampleWebACL"
},
"Capacity": 193,
"ManagedByFirewallManager": false,
"LabelNamespace": "awswaf:ExampleAccountNumber:webacl:exampleWebACL:"
} Create a web ACL with custom request and response handling
The following shows an example web ACL specification. This example includes custom request and response configurations.
YAML
ExampleWebACL:
Type: 'AWS::WAFv2::WebACL'
Properties:
Name: ExampleWebACL1
Scope: REGIONAL
Description: This is an example WebACL
DefaultAction:
Allow:
CustomRequestHandling:
InsertHeaders:
- Name: AllowActionHeader1Name
Value: AllowActionHeader1Value
- Name: AllowActionHeader2Name
Value: AllowActionHeader2Value
VisibilityConfig:
SampledRequestsEnabled: true
CloudWatchMetricsEnabled: true
MetricName: ExampleWebACLMetric
CustomResponseBodies:
CustomResponseBodyKey1:
ContentType: TEXT_PLAIN
Content: this is a plain text
CustomResponseBodyKey2:
ContentType: APPLICATION_JSON
Content: '{"jsonfieldname": "jsonfieldvalue"}'
CustomResponseBodyKey3:
ContentType: TEXT_HTML
Content: <html>HTML text content</html>
Rules:
- Name: RuleWithAWSManagedRules
Priority: 0
OverrideAction:
Count: {}
VisibilityConfig:
SampledRequestsEnabled: true
CloudWatchMetricsEnabled: true
MetricName: RuleWithAWSManagedRulesMetric
Statement:
ManagedRuleGroupStatement:
VendorName: AWS
Name: AWSManagedRulesCommonRuleSet
ExcludedRules: []
- Name: BlockXssAttack
Priority: 1
Action:
Block:
CustomResponse:
ResponseCode: 503
CustomResponseBodyKey: CustomResponseBodyKey1
ResponseHeaders:
- Name: BlockActionHeader1Name
Value: BlockActionHeader1Value
- Name: BlockActionHeader2Name
Value: BlockActionHeader2Value
VisibilityConfig:
SampledRequestsEnabled: true
CloudWatchMetricsEnabled: true
MetricName: BlockXssAttackMetric
Statement:
XssMatchStatement:
FieldToMatch:
AllQueryArguments: {}
TextTransformations:
- Priority: 1
Type: NONEJSON
"ExampleWebACL": {
"Type": "AWS::WAFv2::WebACL",
"Properties": {
"Name": "ExampleWebACL1",
"Scope": "REGIONAL",
"Description": "This is an example WebACL",
"DefaultAction": {
"Allow": {
"CustomRequestHandling": {
"InsertHeaders": [
{
"Name": "AllowActionHeader1Name",
"Value": "AllowActionHeader1Value"
},
{
"Name": "AllowActionHeader2Name",
"Value": "AllowActionHeader2Value"
}
]
}
}
},
"VisibilityConfig": {
"SampledRequestsEnabled": true,
"CloudWatchMetricsEnabled": true,
"MetricName": "ExampleWebACLMetric"
},
"CustomResponseBodies": {
"CustomResponseBodyKey1": {
"ContentType": "TEXT_PLAIN",
"Content": "this is a plain text"
},
"CustomResponseBodyKey2": {
"ContentType": "APPLICATION_JSON",
"Content": "{\"jsonfieldname\": \"jsonfieldvalue\"}"
},
"CustomResponseBodyKey3": {
"ContentType": "TEXT_HTML",
"Content": "<html>HTML text content</html>"
}
},
"Rules": [
{
"Name": "RuleWithAWSManagedRules",
"Priority": 0,
"OverrideAction": {
"Count": {}
},
"VisibilityConfig": {
"SampledRequestsEnabled": true,
"CloudWatchMetricsEnabled": true,
"MetricName": "RuleWithAWSManagedRulesMetric"
},
"Statement": {
"ManagedRuleGroupStatement": {
"VendorName": "AWS",
"Name": "AWSManagedRulesCommonRuleSet",
"ExcludedRules": []
}
}
},
{
"Name": "BlockXssAttack",
"Priority": 1,
"Action": {
"Block": {
"CustomResponse": {
"ResponseCode": 503,
"CustomResponseBodyKey": "CustomResponseBodyKey1",
"ResponseHeaders": [
{
"Name": "BlockActionHeader1Name",
"Value": "BlockActionHeader1Value"
},
{
"Name": "BlockActionHeader2Name",
"Value": "BlockActionHeader2Value"
}
]
}
}
},
"VisibilityConfig": {
"SampledRequestsEnabled": true,
"CloudWatchMetricsEnabled": true,
"MetricName": "BlockXssAttackMetric"
},
"Statement": {
"XssMatchStatement": {
"FieldToMatch": {
"AllQueryArguments": {}
},
"TextTransformations": [
{
"Priority": 1,
"Type": "NONE"
}
]
}
}
}
]
}
}Create a web ACL with JSON body parsing
The following shows an example web ACL specification. This example includes inspection of the web request body as JSON.
YAML
ExampleWebACL:
Type: 'AWS::WAFv2::WebACL'
Properties:
Name: TestingJsonBody
Scope: REGIONAL
Description: WebACL for JsonBody Testing
DefaultAction:
Allow: {}
VisibilityConfig:
SampledRequestsEnabled: true
CloudWatchMetricsEnabled: true
MetricName: ExampleWebACLMetric
Rules:
- Name: TestJsonBodyRule
Priority: 0
Action:
Block: {}
VisibilityConfig:
SampledRequestsEnabled: true
CloudWatchMetricsEnabled: true
MetricName: JsonBodyMatchMetric
Statement:
ByteMatchStatement:
FieldToMatch:
JsonBody:
MatchPattern:
IncludedPaths:
- /foo
- /bar
MatchScope: VALUE
InvalidFallbackBehavior: MATCH
PositionalConstraint: EXACTLY
SearchString: BadBot
TextTransformations:
- Type: NONE
Priority: 0 JSON
"ExampleWebACL": {
"Type": "AWS::WAFv2::WebACL",
"Properties": {
"Name": "TestingJsonBody",
"Scope": "REGIONAL",
"DefaultAction":
{
"Allow":
{}
},
"Description": "WebACL for JsonBody Testing",
"Rules": [
{
"Name": "TestJsonBodyRule",
"Priority": 1,
"Statement": {
"ByteMatchStatement": {
"SearchString": "BadBot",
"FieldToMatch": {
"JsonBody": {
"MatchPattern": {
"IncludedPaths": [
"/foo", "/bar"
]
},
"MatchScope": "VALUE",
"InvalidFallbackBehavior": "MATCH"
}
},
"TextTransformations": [
{
"Priority": 1,
"Type": "NONE"
}
],
"PositionalConstraint": "EXACTLY"
}
},
"Action": {
"Block": {}
},
"VisibilityConfig": {
"SampledRequestsEnabled": true,
"CloudWatchMetricsEnabled": true,
"MetricName": "JsonBodyMatchMetric"
}
} ],
"VisibilityConfig": {
"SampledRequestsEnabled": true,
"CloudWatchMetricsEnabled": true,
"MetricName": "TestingJsonBodyMetric"
}
}
} 