Stops processing on a successful match and allows transaction to proceed.

Marks the transaction for logging in the audit log.

When used together with the regular expression operator capture action will create copies of regular expression captures and place them into the transaction variable collection. Up to ten captures will be copied on a successful pattern match, each with a name consisting of a digit from 0 to 9.

Chains the rule where the action is placed with the rule that immediately follows it. The result is called a rule chain.

# Refuse to accept POST requests that do
# not specify request body length
SecRule REQUEST_METHOD ^POST$ chain
SecRule REQUEST_HEADER:Content-Length ^$

The ctl action allows configuration options to be updated for the transaction. The following configuration options are supported:

With the exception of requestBodyProcessor, each configuration option corresponds to one configuration directive and the usage is identical.

The requestBodyProcessor option allows you to configure the request body processor. By default ModSecurity will use the URLENCODED and MULTIPART processors to process an application/x-www-form-urlencoded and a multipart/form-data body, respectively. A third processor, XML, is also supported, but it is never used implicitly. Instead you must tell ModSecurity to use it by placing a few rules in the REQUEST_HEADERS processing phase.

# Parse requests with Content-Type "text/xml" as XML
SecRule REQUEST_CONTENT_TYPE ^text/xml nolog,pass,ctl:requestBodyProcessor=XML

After the request body was processed as XML you will be able to use the XML-related features to inspect it.

Stops rule processing and intercepts transaction.

Decrement counter based on its age. The following example will decrement the counter by 60 every 300 seconds.

deprecatevar:session.score=60/300

Counter values are always positive, meaning the value will never go below zero.

Note: causes error message to appear in the log "(9)Bad file descriptor: core_output_filter: writing data to the network"

Executes an external script/binary supplied as parameter.

Configures collection variable to expire after the given time in seconds.

expirevar:session.suspicious=3600

Assigns a unique ID to the rule or chain.

Initialises a named persistent collection, either by loading data from storage or by creating a new collection in memory. The following example initiates IP address tracking.

initcol:ip=%{REMOTE_ADDR}

Every collection contains several built-in variables that are read-only:

Collections are loaded into memory when the initcol action is encountered. The collection in storage will be updated (and the appropriate counters increased) only if it was changed during transaction processing.

Indicates that a successful match of the rule needs to be logged.

Assigns a custom message to the rule or chain.

If enabled ModSecurity will perform multiple operator invocations for every target, before and after every anti-evasion transformation is performed.

Indicates that a successful match of the rule should not be used as criteria whether the transaction should be logged to the audit log.

Prevents rule matches from appearing in the log.

Continues processing with the next rule in spite of a successful match. Transaction will not be interrupted but it will be logged (unless logging has been suppressed).

Pauses transaction processing for the specified number of milliseconds.

Places the rule (or the rule chain) into one of five available processing phases.

Intercepts transaction by forwarding request to another web server using the proxy backend.

Intercepts transaction by issuing a redirect to the given location. If the status action is present and its value is acceptable (301, 302, 303, or 307) it will be used for the redirection. Otherwise status code 302 will be used.

Specifies rule revision. This action is used in combination with the id action to allow the same rule ID to be used after changes take place but to still provide some indication the rule changed.

Sanitises (replaces each byte with an asterisk) a named request argument prior to audit logging.

sanitiseArg:password

Sanitises the variable (request argument, request header, or response header) that caused a rule match. This action can be used to sanitise arbitrary transaction elements when they match a condition. For example, the example below will sanitise any argument that contains the word password in the name.

SecRule ARGS_NAMES password nolog,pass,sanitiseMatched

Sanitises a named request header.

sanitiseRequestHeader:Authorization

Sanitises a names response header.

Assigns severity to the rule it is placed with.

Special-purpose action that initialises the USER collection. After initialisation takes place the variable USERID will be available for use in the subsequent rules.

Special-purpose action that initialises the SESSION collection. On first invocation of this action the collection will be empty (not taking the pre-defined variables into account - see initcol for more information). On subsequent invocations the contents of the collection (session, in this case) will be retrieved from storage. After initialisation takes place the variable SESSIONID will be available for use in the subsequent rules.

# Initialise session variables using the session cookie value
SecRule REQUEST_COOKIES:PHPSESSID !^$ chain,nolog,pass
SecAction setsid:%{REQUEST_COOKIES.PHPSESSID}

This action understands each application maintains its own set of sessions. It will utilise the current web application ID to create a session namespace.

Creates, removes, or updates an environment variable. This action can be used to establish communication with other Apache modules.

To create a new variable (if you omit the value 1 will be used):

setenv:name=value

To remove a variable:

setenv:!name

Creates, removes, or updates a variable in the specified collection.

To create a new variable:

setvar:tx.score=10

To remove a variable prefix the name with exclamation mark:

setvar:!tx.score

To increase or decrease variable value use + and - characters in front of a numerical value:

setvar:tx.score=+5

Skips one or more rules (or chains) on successful match. This action can not be used to skip rules within one chain.

Accepts a single paramater denoting the number of rules (or chains) to skip.

skip:3

Specifies the response status code to use with actions deny and redirect.

This action can be used which transformation function should be used against the specified variables before they (or the results, rather) are run against the operator specified in the rule.

This action should be used together with an XPath expression to register a namespace.