Documentation

A rule statement that defines a string match search for WAF to apply to web requests. The byte match statement provides the bytes to search for, the location in requests that you want WAF to search, and other settings. The bytes to search for are typically a string that corresponds with ASCII characters. In the WAF console and the developer guide, this is called a string match statement.

See: newByteMatchStatement smart constructor.

Create a value of ByteMatchStatement with all optional fields omitted.

Use generic-lens or optics to modify other optional fields.

The following record fields are available, with the corresponding lenses provided for backwards compatibility:

$sel:searchString:ByteMatchStatement', byteMatchStatement_searchString - A string value that you want WAF to search for. WAF searches only in the part of web requests that you designate for inspection in FieldToMatch. The maximum length of the value is 50 bytes.

Valid values depend on the component that you specify for inspection in FieldToMatch:

• Method: The HTTP method that you want WAF to search for. This indicates the type of operation specified in the request.
• UriPath: The value that you want WAF to search for in the URI path, for example, /images/daily-ad.jpg.

If SearchString includes alphabetic characters A-Z and a-z, note that the value is case sensitive.

If you're using the WAF API

Specify a base64-encoded version of the value. The maximum length of the value before you base64-encode it is 50 bytes.

For example, suppose the value of Type is HEADER and the value of Data is User-Agent. If you want to search the User-Agent header for the value BadBot, you base64-encode BadBot using MIME base64-encoding and include the resulting value, QmFkQm90, in the value of SearchString.

If you're using the CLI or one of the Amazon Web Services SDKs

The value that you want WAF to search for. The SDK automatically base64 encodes the value.-- -- Note: This Lens automatically encodes and decodes Base64 data. -- The underlying isomorphism will encode to Base64 representation during -- serialisation, and decode from Base64 representation during deserialisation. -- This Lens accepts and returns only raw unencoded data.

$sel:fieldToMatch:ByteMatchStatement', byteMatchStatement_fieldToMatch - The part of the web request that you want WAF to inspect.

$sel:textTransformations:ByteMatchStatement', byteMatchStatement_textTransformations - Text transformations eliminate some of the unusual formatting that attackers use in web requests in an effort to bypass detection. If you specify one or more transformations in a rule statement, WAF performs all transformations on the content of the request component identified by FieldToMatch, starting from the lowest priority setting, before inspecting the content for a match.

$sel:positionalConstraint:ByteMatchStatement', byteMatchStatement_positionalConstraint - The area within the portion of the web request that you want WAF to search for SearchString. Valid values include the following:

CONTAINS

The specified part of the web request must include the value of SearchString, but the location doesn't matter.

CONTAINS_WORD

The specified part of the web request must include the value of SearchString, and SearchString must contain only alphanumeric characters or underscore (A-Z, a-z, 0-9, or _). In addition, SearchString must be a word, which means that both of the following are true:

• SearchString is at the beginning of the specified part of the web request or is preceded by a character other than an alphanumeric character or underscore (_). Examples include the value of a header and ;BadBot.
• SearchString is at the end of the specified part of the web request or is followed by a character other than an alphanumeric character or underscore (_), for example, BadBot; and -BadBot;.

EXACTLY

The value of the specified part of the web request must exactly match the value of SearchString.

STARTS_WITH

The value of SearchString must appear at the beginning of the specified part of the web request.

ENDS_WITH

The value of SearchString must appear at the end of the specified part of the web request.

A string value that you want WAF to search for. WAF searches only in the part of web requests that you designate for inspection in FieldToMatch. The maximum length of the value is 50 bytes.

Valid values depend on the component that you specify for inspection in FieldToMatch:

• Method: The HTTP method that you want WAF to search for. This indicates the type of operation specified in the request.
• UriPath: The value that you want WAF to search for in the URI path, for example, /images/daily-ad.jpg.

If SearchString includes alphabetic characters A-Z and a-z, note that the value is case sensitive.

If you're using the WAF API

Specify a base64-encoded version of the value. The maximum length of the value before you base64-encode it is 50 bytes.

For example, suppose the value of Type is HEADER and the value of Data is User-Agent. If you want to search the User-Agent header for the value BadBot, you base64-encode BadBot using MIME base64-encoding and include the resulting value, QmFkQm90, in the value of SearchString.

If you're using the CLI or one of the Amazon Web Services SDKs

The value that you want WAF to search for. The SDK automatically base64 encodes the value.-- -- Note: This Lens automatically encodes and decodes Base64 data. -- The underlying isomorphism will encode to Base64 representation during -- serialisation, and decode from Base64 representation during deserialisation. -- This Lens accepts and returns only raw unencoded data.

The part of the web request that you want WAF to inspect.

Text transformations eliminate some of the unusual formatting that attackers use in web requests in an effort to bypass detection. If you specify one or more transformations in a rule statement, WAF performs all transformations on the content of the request component identified by FieldToMatch, starting from the lowest priority setting, before inspecting the content for a match.

The area within the portion of the web request that you want WAF to search for SearchString. Valid values include the following:

CONTAINS

The specified part of the web request must include the value of SearchString, but the location doesn't matter.

CONTAINS_WORD

The specified part of the web request must include the value of SearchString, and SearchString must contain only alphanumeric characters or underscore (A-Z, a-z, 0-9, or _). In addition, SearchString must be a word, which means that both of the following are true:

• SearchString is at the beginning of the specified part of the web request or is preceded by a character other than an alphanumeric character or underscore (_). Examples include the value of a header and ;BadBot.
• SearchString is at the end of the specified part of the web request or is followed by a character other than an alphanumeric character or underscore (_), for example, BadBot; and -BadBot;.

EXACTLY

The value of the specified part of the web request must exactly match the value of SearchString.

STARTS_WITH

The value of SearchString must appear at the beginning of the specified part of the web request.

ENDS_WITH

The value of SearchString must appear at the end of the specified part of the web request.