Regex match rule statement - Amazon WAF, Amazon Firewall Manager, and Amazon Shield Advanced
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Regex match rule statement

A regex match statement instructs Amazon WAF to match a request component against a single regular expression (regex). A web request matches the statement if the request component matches the regex that you specify.

This statement type is a good alternative to the Regex pattern set match rule statement for situations where you want to combine your matching criteria using mathematical logic. For example, if you want a request component to match against some regex patterns and to not match against others, you can combine the regex match statements using the AND rule statement and the NOT rule statement.

Amazon WAF supports the pattern syntax used by the PCRE library libpcre with some exceptions. The library is documented at PCRE - Perl Compatible Regular Expressions. For information about Amazon WAF support, see Regular expression pattern matching in Amazon WAF.

Nestable – You can nest this statement type.

WCUs – 3 WCUs, as a base cost. If you use the request component All query parameters, add 10 WCUs. If you use the request component JSON body, double the base cost WCUs. For each Text transformation that you apply, add 10 WCUs.

This statement type operates on a web request component, and requires the following request component settings:

  • Request component – The part of the web request to inspect, for example, a query string or the body.


    If you inspect the request components Body, JSON body, Headers, or Cookies, read about the limitations on how much content Amazon WAF can inspect at Handling of oversize request components in Amazon WAF.

    For information about web request components, see Web request component specification and handling.

  • Optional text transformations – Transformations that you want Amazon WAF to perform on the request component before inspecting it. For example, you could transform to lowercase or normalize white space. If you specify more than one transformation, Amazon WAF processes them in the order listed. For information, see Text transformation options.

Where to find this rule statement
  • Rule builder on the console – For Match type, choose Matches regular expression.

  • APIRegexMatchStatement