AWS::WAFv2::WebACL TextTransformation - AWS CloudFormation

AWS::WAFv2::WebACL TextTransformation

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.

Text transformations eliminate some of the unusual formatting that attackers use in web requests in an effort to bypass detection.

Syntax

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

JSON

{ "Priority" : Integer, "Type" : String }

YAML

Priority: Integer Type: String

Properties

Priority

Sets the relative processing order for multiple transformations that are defined for a rule statement. AWS WAF processes all transformations, from lowest priority to highest, before inspecting the transformed content. The priorities don't need to be consecutive, but they must all be different.

Required: Yes

Type: Integer

Minimum: 0

Update requires: No interruption

Type

You can specify the following transformation types:

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.

NONE

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

Required: Yes

Type: String

Allowed Values: CMD_LINE | COMPRESS_WHITE_SPACE | HTML_ENTITY_DECODE | LOWERCASE | NONE | URL_DECODE

Update requires: No interruption