This is the new *CloudFormation Template Reference Guide*. Please update your bookmarks and links. For help getting started with CloudFormation, see the [AWS CloudFormation User Guide](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/Welcome.html).

# AWS::WAF::ByteMatchSet FieldToMatch
<a name="aws-properties-waf-bytematchset-fieldtomatch"></a>

**Note**  
AWS WAF Classic support will end on September 30, 2025.   
This is **AWS WAF Classic** documentation. For more information, see [AWS WAF Classic](https://docs.aws.amazon.com/waf/latest/developerguide/classic-waf-chapter.html) in the developer guide.  
**For the latest version of AWS WAF**, use the AWS WAFV2 API and see the [AWS WAF Developer Guide](https://docs.aws.amazon.com/waf/latest/developerguide/waf-chapter.html). With the latest version, AWS WAF has a single set of endpoints for regional and global use. 

Specifies where in a web request to look for `TargetString`.

## Syntax
<a name="aws-properties-waf-bytematchset-fieldtomatch-syntax"></a>

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

### JSON
<a name="aws-properties-waf-bytematchset-fieldtomatch-syntax.json"></a>

```
{
  "[Data](#cfn-waf-bytematchset-fieldtomatch-data)" : String,
  "[Type](#cfn-waf-bytematchset-fieldtomatch-type)" : String
}
```

### YAML
<a name="aws-properties-waf-bytematchset-fieldtomatch-syntax.yaml"></a>

```
  [Data](#cfn-waf-bytematchset-fieldtomatch-data): String
  [Type](#cfn-waf-bytematchset-fieldtomatch-type): String
```

## Properties
<a name="aws-properties-waf-bytematchset-fieldtomatch-properties"></a>

`Data`  <a name="cfn-waf-bytematchset-fieldtomatch-data"></a>
When the value of `Type` is `HEADER`, enter the name of the header that you want AWS WAF to search, for example, `User-Agent` or `Referer`. The name of the header is not case sensitive.  
When the value of `Type` is `SINGLE_QUERY_ARG`, enter the name of the parameter that you want AWS WAF to search, for example, `UserName` or `SalesRegion`. The parameter name is not case sensitive.  
If the value of `Type` is any other value, omit `Data`.  
*Required*: No  
*Type*: String  
*Pattern*: `.*\S.*`  
*Minimum*: `1`  
*Maximum*: `128`  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`Type`  <a name="cfn-waf-bytematchset-fieldtomatch-type"></a>
The part of the web request that you want AWS WAF to search for a specified string. Parts of a request that you can search include the following:  
+ `HEADER`: A specified request header, for example, the value of the `User-Agent` or `Referer` header. If you choose `HEADER` for the type, specify the name of the header in `Data`.
+ `METHOD`: The HTTP method, which indicated the type of operation that the request is asking the origin to perform. Amazon CloudFront supports the following methods: `DELETE`, `GET`, `HEAD`, `OPTIONS`, `PATCH`, `POST`, and `PUT`.
+ `QUERY_STRING`: A query string, which is the part of a URL that appears after a `?` character, if any.
+ `URI`: The part of a web request that identifies a resource, for example, `/images/daily-ad.jpg`.
+ `BODY`: The part of a request that contains any additional data that you want to send to your web server as the HTTP request body, such as data from a form. The request body immediately follows the request headers. Note that only the first `8192` bytes of the request body are forwarded to AWS WAF for inspection. To allow or block requests based on the length of the body, you can create a size constraint set.
+ `SINGLE_QUERY_ARG`: The parameter in the query string that you will inspect, such as *UserName* or *SalesRegion*. The maximum length for `SINGLE_QUERY_ARG` is 30 characters.
+ `ALL_QUERY_ARGS`: Similar to `SINGLE_QUERY_ARG`, but rather than inspecting a single parameter, AWS WAF will inspect all parameters within the query for the value or regex pattern that you specify in `TargetString`.
*Required*: Yes  
*Type*: String  
*Allowed values*: `URI | QUERY_STRING | HEADER | METHOD | BODY | SINGLE_QUERY_ARG | ALL_QUERY_ARGS`  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)