ByteMatchTuple
Note
Deprecation notice: AWS WAF Classic support will end on September 30, 2025.
This is AWS WAF Classic documentation. For more information, see AWS WAF Classic in the developer guide.
For the latest version of AWS WAF , use the AWS WAFV2 API and see the AWS WAF Developer Guide. With the latest version, AWS WAF has a single set of endpoints for regional and global use.
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.
Contents
- FieldToMatch
-
The part of a web request that you want AWS WAF to search, such as a specified header or a query string. For more information, see FieldToMatch.
Type: FieldToMatch object
Required: Yes
- PositionalConstraint
-
Within the portion of a web request that you want to search (for example, in the query string, if any), specify where you want AWS WAF to search. Valid values include the following:
CONTAINS
The specified part of the web request must include the value of
TargetString
, but the location doesn't matter.CONTAINS_WORD
The specified part of the web request must include the value of
TargetString
, andTargetString
must contain only alphanumeric characters or underscore (A-Z, a-z, 0-9, or _). In addition,TargetString
must be a word, which means one of the following:-
TargetString
exactly matches the value of the specified part of the web request, such as the value of a header. -
TargetString
is at the beginning of the specified part of the web request and is followed by a character other than an alphanumeric character or underscore (_), for example,BadBot;
. -
TargetString
is at the end of the specified part of the web request and is preceded by a character other than an alphanumeric character or underscore (_), for example,;BadBot
. -
TargetString
is in the middle of the specified part of the web request and is preceded and followed by characters other than alphanumeric characters or underscore (_), for example,-BadBot;
.
EXACTLY
The value of the specified part of the web request must exactly match the value of
TargetString
.STARTS_WITH
The value of
TargetString
must appear at the beginning of the specified part of the web request.ENDS_WITH
The value of
TargetString
must appear at the end of the specified part of the web request.Type: String
Valid Values:
EXACTLY | STARTS_WITH | ENDS_WITH | CONTAINS | CONTAINS_WORD
Required: Yes
-
- TargetString
-
The value that you want AWS WAF to search for. AWS WAF searches for the specified string in the part of web requests that you specified in
FieldToMatch
. The maximum length of the value is 50 bytes.Valid values depend on the values that you specified for
FieldToMatch
:-
HEADER
: The value that you want AWS WAF to search for in the request header that you specified in FieldToMatch, for example, the value of theUser-Agent
orReferer
header. -
METHOD
: The HTTP method, which indicates the type of operation specified in the request. Amazon CloudFront supports the following methods:DELETE
,GET
,HEAD
,OPTIONS
,PATCH
,POST
, andPUT
. -
QUERY_STRING
: The value that you want AWS WAF to search for in the query string, which is the part of a URL that appears after a?
character. -
URI
: The path component of the URI. This does not include the query string or fragment components of the URI. For information, see Uniform Resource Identifier (URI): Generic Syntax. -
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 first8192
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 CreateSizeConstraintSet. -
SINGLE_QUERY_ARG
: The parameter in the query string that you will inspect, such as UserName or SalesRegion. The maximum length forSINGLE_QUERY_ARG
is 30 characters. -
ALL_QUERY_ARGS
: Similar toSINGLE_QUERY_ARG
, but instead of inspecting a single parameter, AWS WAF inspects all parameters within the query string for the value or regex pattern that you specify inTargetString
.
If
TargetString
includes alphabetic characters A-Z and a-z, note that the value is case sensitive.If you're using the AWS 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
isHEADER
and the value ofData
isUser-Agent
. If you want to search theUser-Agent
header for the valueBadBot
, you base64-encodeBadBot
using MIME base64-encoding and include the resulting value,QmFkQm90
, in the value ofTargetString
.If you're using the AWS CLI or one of the AWS SDKs
The value that you want AWS WAF to search for. The SDK automatically base64 encodes the value.
Type: Base64-encoded binary data object
Required: Yes
-
- TextTransformation
-
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 it for a match.You can only specify a single type of TextTransformation.
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 to perform any text transformations.Type: String
Valid Values:
NONE | COMPRESS_WHITE_SPACE | HTML_ENTITY_DECODE | LOWERCASE | CMD_LINE | URL_DECODE
Required: Yes
-
See Also
For more information about using this API in one of the language-specific AWS SDKs, see the following: