AWS CloudFormation
User Guide (Version )

AWS::WAF::ByteMatchSet

The AWS::WAF::ByteMatchSet resource creates an AWS WAF ByteMatchSet that identifies a part of a web request that you want to inspect.

Syntax

To declare this entity in your AWS CloudFormation template, use the following syntax:

JSON

{ "Type" : "AWS::WAF::ByteMatchSet", "Properties" : { "ByteMatchTuples" : [ ByteMatchTuple, ... ], "Name" : String } }

YAML

Type: AWS::WAF::ByteMatchSet Properties: ByteMatchTuples: - ByteMatchTuple Name: String

Properties

ByteMatchTuples

Specifies the bytes (typically a string that corresponds with ASCII characters) that you want AWS WAF to search for in web requests, the location in requests that you want AWS WAF to search, and other settings.

Required: No

Type: List of ByteMatchTuple

Update requires: No interruption

Name

A friendly name or description of the ByteMatchSet. You can't change Name after you create a ByteMatchSet.

Required: Yes

Type: String

Minimum: 1

Maximum: 128

Update requires: Replacement

Return Values

Ref

When you pass the logical ID of this resource to the intrinsic Ref function, Ref returns the resource physical ID, such as 1234a1a-a1b1-12a1-abcd-a123b123456.

For more information about using the Ref function, see Ref.

Examples

HTTP Referers

The following example defines a set of HTTP referers to match.

JSON

"BadReferers": { "Type": "AWS::WAF::ByteMatchSet", "Properties": { "Name": "ByteMatch for matching bad HTTP referers", "ByteMatchTuples": [ { "FieldToMatch" : { "Type": "HEADER", "Data": "referer" }, "TargetString" : "badrefer1", "TextTransformation" : "NONE", "PositionalConstraint" : "CONTAINS" }, { "FieldToMatch" : { "Type": "HEADER", "Data": "referer" }, "TargetString" : "badrefer2", "TextTransformation" : "NONE", "PositionalConstraint" : "CONTAINS" } ] } }

YAML

BadReferers: Type: "AWS::WAF::ByteMatchSet" Properties: Name: "ByteMatch for matching bad HTTP referers" ByteMatchTuples: - FieldToMatch: Type: "HEADER" Data: "referer" TargetString: "badrefer1" TextTransformation: "NONE" PositionalConstraint: "CONTAINS" - FieldToMatch: Type: "HEADER" Data: "referer" TargetString: "badrefer2" TextTransformation: "NONE" PositionalConstraint: "CONTAINS"

Associate a ByteMatchSet with a Web ACL Rule

The following example associates the BadReferers byte match set with a web access control list (ACL) rule.

JSON

"BadReferersRule" : { "Type": "AWS::WAF::Rule", "Properties": { "Name": "BadReferersRule", "MetricName" : "BadReferersRule", "Predicates": [ { "DataId" : { "Ref" : "BadReferers" }, "Negated" : false, "Type" : "ByteMatch" } ] } }

YAML

BadReferersRule: Type: "AWS::WAF::Rule" Properties: Name: "BadReferersRule" MetricName: "BadReferersRule" Predicates: - DataId: Ref: "BadReferers" Negated: false Type: "ByteMatch"

Create a Web ACL

The following example associates the BadReferersRule rule with a web ACL. The web ACL allows all requests except for ones with referers that match the BadReferersRule rule.

JSON

"MyWebACL": { "Type": "AWS::WAF::WebACL", "Properties": { "Name": "WebACL to block blacklisted IP addresses", "DefaultAction": { "Type": "ALLOW" }, "MetricName" : "MyWebACL", "Rules": [ { "Action" : { "Type" : "BLOCK" }, "Priority" : 1, "RuleId" : { "Ref" : "BadReferersRule" } } ] } }

YAML

MyWebACL: Type: "AWS::WAF::WebACL" Properties: Name: "WebACL to block blacklisted IP addresses" DefaultAction: Type: "ALLOW" MetricName: "MyWebACL" Rules: - Action: Type: "BLOCK" Priority: 1 RuleId: Ref: "BadReferersRule"