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[ aws . waf ]

create-size-constraint-set

Description

Creates a SizeConstraintSet . You then use update-size-constraint-set to identify the part of a web request that you want AWS WAF to check for length, such as the length of the User-Agent header or the length of the query string. For example, you can create a SizeConstraintSet that matches any requests that have a query string that is longer than 100 bytes. You can then configure AWS WAF to reject those requests.

To create and configure a SizeConstraintSet , perform the following steps:

  • Use get-change-token to get the change token that you provide in the change-token parameter of a create-size-constraint-set request.
  • Submit a create-size-constraint-set request.
  • Use get-change-token to get the change token that you provide in the change-token parameter of an update-size-constraint-set request.
  • Submit an update-size-constraint-set request to specify the part of the request that you want AWS WAF to inspect (for example, the header or the URI) and the value that you want AWS WAF to watch for.

For more information about how to use the AWS WAF API to allow or block HTTP requests, see the AWS WAF Developer Guide .

See also: AWS API Documentation

Synopsis

  create-size-constraint-set
--name <value>
--change-token <value>
[--cli-input-json <value>]
[--generate-cli-skeleton <value>]

Options

--name (string)

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

--change-token (string)

The value returned by the most recent call to get-change-token .

--cli-input-json (string) Performs service operation based on the JSON string provided. The JSON string follows the format provided by --generate-cli-skeleton. If other arguments are provided on the command line, the CLI values will override the JSON-provided values.

--generate-cli-skeleton (string) Prints a JSON skeleton to standard output without sending an API request. If provided with no value or the value input, prints a sample input JSON that can be used as an argument for --cli-input-json. If provided with the value output, it validates the command inputs and returns a sample output JSON for that command.

Output

SizeConstraintSet -> (structure)

A SizeConstraintSet that contains no SizeConstraint objects.

SizeConstraintSetId -> (string)

A unique identifier for a SizeConstraintSet . You use SizeConstraintSetId to get information about a SizeConstraintSet (see get-size-constraint-set ), update a SizeConstraintSet (see update-size-constraint-set ), insert a SizeConstraintSet into a Rule or delete one from a Rule (see update-rule ), and delete a SizeConstraintSet from AWS WAF (see delete-size-constraint-set ).

SizeConstraintSetId is returned by create-size-constraint-set and by list-size-constraint-sets .

Name -> (string)

The name, if any, of the SizeConstraintSet .

SizeConstraints -> (list)

Specifies the parts of web requests that you want to inspect the size of.

(structure)

Specifies a constraint on the size of a part of the web request. AWS WAF uses the Size , ComparisonOperator , and FieldToMatch to build an expression in the form of "Size ComparisonOperator size in bytes of FieldToMatch ". If that expression is true, the SizeConstraint is considered to match.

FieldToMatch -> (structure)

Specifies where in a web request to look for the size constraint.

Type -> (string)

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. For more information, see create-size-constraint-set .

Data -> (string)

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 . If the value of Type is any other value, omit Data .

The name of the header is not case sensitive.

TextTransformation -> (string)

Text transformations eliminate some of the unusual formatting that attackers use in web requests in an effort to bypass AWS WAF. If you specify a transformation, AWS WAF performs the transformation on FieldToMatch before inspecting a request for a match.

Note that if you choose BODY for the value of Type , you must choose NONE for TextTransformation because CloudFront forwards only the first 8192 bytes for inspection.

NONE

Specify NONE if you don't want to perform any text transformations.

CMD_LINE

When you're concerned that attackers are injecting an operating system command line command and using unusual formatting to disguise some or all of the command, use this option to perform the following transformations:

  • Delete the following characters: " ' ^
  • Delete spaces before the following characters: / (
  • Replace the following characters with a space: , ;
  • Replace multiple spaces with one space
  • Convert uppercase letters (A-Z) to lowercase (a-z)
COMPRESS_WHITE_SPACE

Use this option to replace the following characters with a space character (decimal 32):

  • f, formfeed, decimal 12
  • t, tab, decimal 9
  • n, newline, decimal 10
  • r, carriage return, decimal 13
  • v, vertical tab, decimal 11
  • non-breaking space, decimal 160

COMPRESS_WHITE_SPACE also replaces multiple spaces with one space.

HTML_ENTITY_DECODE

Use this option to replace HTML-encoded characters with unencoded characters. HTML_ENTITY_DECODE performs the following operations:

  • Replaces (ampersand)quot; with "
  • Replaces (ampersand)nbsp; with a non-breaking space, decimal 160
  • Replaces (ampersand)lt; with a "less than" symbol
  • Replaces (ampersand)gt; with ````
  • Replaces characters that are represented in hexadecimal format, (ampersand)#xhhhh; , with the corresponding characters
  • Replaces characters that are represented in decimal format, (ampersand)#nnnn; , with the corresponding characters
LOWERCASE

Use this option to convert uppercase letters (A-Z) to lowercase (a-z).

URL_DECODE

Use this option to decode a URL-encoded value.

ComparisonOperator -> (string)

The type of comparison you want AWS WAF to perform. AWS WAF uses this in combination with the provided Size and FieldToMatch to build an expression in the form of "Size ComparisonOperator size in bytes of FieldToMatch ". If that expression is true, the SizeConstraint is considered to match.

EQ : Used to test if the Size is equal to the size of the FieldToMatch

NE : Used to test if the Size is not equal to the size of the FieldToMatch

LE : Used to test if the Size is less than or equal to the size of the FieldToMatch

LT : Used to test if the Size is strictly less than the size of the FieldToMatch

GE : Used to test if the Size is greater than or equal to the size of the FieldToMatch

GT : Used to test if the Size is strictly greater than the size of the FieldToMatch

Size -> (long)

The size in bytes that you want AWS WAF to compare against the size of the specified FieldToMatch . AWS WAF uses this in combination with ComparisonOperator and FieldToMatch to build an expression in the form of "Size ComparisonOperator size in bytes of FieldToMatch ". If that expression is true, the SizeConstraint is considered to match.

Valid values for size are 0 - 21474836480 bytes (0 - 20 GB).

If you specify URI for the value of Type , the / in the URI counts as one character. For example, the URI /logo.jpg is nine characters long.

ChangeToken -> (string)

The change-token that you used to submit the create-size-constraint-set request. You can also use this value to query the status of the request. For more information, see get-change-token-status .