Bot Rules

This feature is in BETA status. Please contact your account manager to preview this feature on your account.

Use bot rules to require a client (e.g., a web browser) to solve a challenge before resolving the request. WAF blocks traffic when the client cannot solve this challenge within a few seconds. Basic bots typically cannot solve this type of challenge and therefore their traffic is blocked. This prevents them from scraping your siteRefers to harvesting data from your site., cardingRefers to the process through which stolen credit cards are authorized., spamming your forms, launching DDoS attacks, and committing ad fraud.

Solving a challenge requires a JavaScript-enabled client. Users that have disabled JavaScript on their browsing session will be unable to access content protected by bot rules.

How Does It Work?

Content protected by bot rules undergoes the following workflow:

1. Browser Challenge

   WAF sends a browser challenge in response to requests for content protected by bot rules. It is up to the client to solve this challenge within a few seconds.

2. Response

   The results of the above browser challenge determines what happens next.

   • Solved: If the client is able to solve the challenge, then our CDN serves the requested content. Additionally, a cookie will be added to the user's session. This cookie instructs our CDN to serve content to the user without requiring a browser challenge. Once the cookie expires, new requests for content protected by bot rules will once again require the client to solve a challenge.

     Define the duration for this cookie through the Valid for (in minutes) option when setting up the enforcement of bot rules within your Security Application Manager configuration.

   • Unsolved: If the client is unable to solve the challenge, then our CDN responds with the status code defined within your Security Application Manager configuration.

Bot Rule Sets

A bot rule set defines the set of requests that will be protected by bot rules. Each rule contains:

• Up to 6 conditions that define request identification criteria.

• A rule ID and message that will be associated with requests identified by this rule.

  Assigning a unique ID and message to each rule makes it easy to identify requests detected as a result of a specific rule.

  A rule ID must be a number between 77,000,000 and 77,999,999.

A bot rule set may contain up to 10 rules.

Request Identification

WAF identifies a request when it satisfies at least one rule in a bot rule set. A rule is satisfied when a match is found for each of its conditions.

Example #1:

This example assumes that your bot rule set contains the following two rules:

Rule	Description
1	This rule contains a single condition.
2	This rule contains two conditions.

Assuming the above configuration, WAF applies bot rules protection under either of the following circumstances:

• A match is found for the variable defined in the first rule's condition.

• A match is found for the variables defined in both of the second rule's conditions.

Certain variables match on key-value pairs. If you match on multiple keys within a single variable, WAF will only need to find one of those matches to satisfy that variable. For example, if you set up a request header variable to match for Authorization and Content-Type, then requests that contain either or both of those headers will satisfy that variable.

Conditions

A condition determines how requests will be identified through variables, operators, match values, transformations, and negative matching.

Variables

A variable identifies the request element that WAF will analyze. We support the following request elements:

• ASN: Identifies requests by the Autonomous System Number (ASN) associated with the client's IP address.

  Specify a regular expression to match for multiple ASNs.
  Example: 
  Use the following pattern to match for requests from 15133 and 14153:
  15133|14153

• Country: Identifies requests by the country from which the request originated. Specify the desired country using a country code.

  Specify a regular expression to match for multiple country codes.
  Example: 
  Use the following pattern to match for requests from the United States, Canada, and Mexico:
  US|CA|MX

• IP address: Identify requests by the requester's IPv4 and/or IPv6 address. Specify a comma-delimited list of the desired IP address(es) using standard IPv4/IPv6 and CIDR notation. Specify a subnet by appending a slash (/) and the desired bit-length of the prefix (e.g., 11.22.33.0/22). Do not specify more than 1,000 IP addresses or IP blocks.

• Request cookies: Match against all or specific cookies.

  • All: Do not specify the desired cookie within this variable and specify the desired cookie value or pattern within the Match value option.

  • Specific Cookies: Define the name of the desired cookie within this variable and specify the desired cookie value or pattern within the Match value option.

    Setting up a cookie variable also allows you to define whether WAF uses a regular expression, a negative match, or both when comparing the value assigned to the variable against cookies. Use a negative match to find requests whose payload does not contain the specified cookie.

• Request header: Match against all or specific request headers.

  • All: Do not specify the desired request header within this variable and specify the desired header value or pattern within the Match value option.

  • Specific Request Headers: Define the name of the desired request header within this variable and specify the desired header value or pattern within the Match value option.

    Setting up a request header variable also allows you to define whether WAF uses a regular expression, a negative match, or both when comparing the value assigned to the variable against request headers. Use a negative match to find requests whose payload does not contain the specified request header.

• Request method: Match against request method (e.g., GET and POST).

• Request query: Match against the request's query string. Specify the desired value or pattern within the Match value option.

• Request URI: Match against the request's URL path and query string. Define a URL path that starts directly after the hostname. Exclude the protocol and hostname when defining this property.

  Sample values:

  /marketing?id=123456

  /800001/mycustomerorigin

• Request URL path: Match against the request's URL path. Define a URL path that starts directly after the hostname. Exclude the protocol, hostname, and query string when defining this property.

  Sample values:

  /marketing

  /800001/mycustomerorigin

All variables support the ability to match on the number of times that a request element is found within the request. Set up a variable to match on the number of instances instead of inspecting the element for a specific value or regular expression pattern by marking the Count option.

You may define zero or more keys when setting up variables that match on key-value pairs. WAF must find at least one of the specified keys in the request before that variable will be satisfied. For example, if you set up a request header variable to match for Authorization and Content-Type, then requests that contain either or both of those headers will satisfy that variable.

Operators

An operator determines how WAF will compare a match value against the request element identified by a variable.

• Begins with: A match is found when the request element starts with the specified match value.
• Contains: A match is found when the request element contains the specified match value.
• Ends with:  A match is found when the request element ends with the specified match value.
• Exact match:  A match is found when the request element is an exact match to the specified match value.
• Regex: A match is found when the request element satisfies the regular expression defined in the match value.

• Value match: A match is found when the request element occurs the exact number of times defined in the match value.

  The Value match operator should only be used when the Count option has been enabled.

Match Value

WAF uses a match value to identify threats.

• Default: By default, WAF compares a match value against the request element identified by a variable (e.g., URL path or a request header's value).
• Count: Enable the Count option on a variable to compare this value against the number of times that the request element identified by a variable (e.g., a specific cookie or request header) occurs within the request.

Example:

This example assumes the following configuration:

We will now examine how the Count option affects comparisons for this configuration.

• Disabled: If the Count option has been disabled on the variable, then WAF will compare the value of the Authentication request header to 1.
• Enabled: If the Count option has been enabled on the variable, then WAF will compare the number of times that the Authentication request header occurred in the request to 1.

The type of comparison that will be performed is determined by the Operator option.

Match Transformations

WAF can transform the source value before it inspects it. Select one or more of the following transformations to allow WAF to compare the match value against the result of each selected transformation:

• Lowercase: Converts all uppercase characters to lowercase characters.
• None: The source value will not be modified.
• Remove nulls: Removes all null values from the source value.
• URL decode: Applies URL decoding to the source value. This transformation is useful when the source value has been URL encoded twice.

Bot Rule Administration

You may create, modify, and delete bot rule sets.

Key information:

• Administer bot rule sets from the Bot Rules page.
• Apply a bot rule set to production traffic by adding it to a Security Application Manager configuration and then determining how it will be enforced. Multiple Security Application Manager configurations may use the same bot rule set. Leverage this capability to tailor security screening by application or traffic profile.
• It may take up to 2 minutes for an updated bot rule set to be applied across our entire network.

To create a bot rule set

1. Navigate to the Bot Rules page. How?From the main menu, navigate to More | WAF | WAF Tier | Security Rule Manager | Bot Rules.

2. Click Add Bot Rule.
3. In the Name option, type the unique name by which this bot rule set will be identified. This name should be sufficiently descriptive to identify it when setting up a Security Application Manager configuration.
4. Each new bot rule set contains a default rule that appears directly below the Name option. Find the Name option for that default rule and set it to a name that identifies the purpose of this rule.
5. In the Rule ID option, specify a number between 77,000,000 and 77,999,999.
6. In the Rule message option, type a brief description for this rule.

7. The default rule contains a default condition. Modify this condition to determine how WAF will identify requests.

   1. From the condition's Variable option, select the request element through which WAF will identify requests.

      Learn more about variables.

   2. Certain variables (e.g., request cookies and request header) match on name and value. If you have selected this type of variable, then perform the following steps:

      1. Click + Add Match.

      2. From the Name option, type the desired name.

         For example, match for requests that contain an Authorization header by setting this option to Authorization.

      3. Optional. Mark the Negative Match option to match for requests that do not contain a matching value for the name defined in the previous step.
      4. If you specified a regular expression in the Name option, then you should mark the Regex Match option.
      5. Optional. Add another match through which this variable can be satisfied by repeating steps a - d.

   3. Optional. Mark the Count option to match by the number of instances that a match is found instead of by inspecting that request element.

      Learn more.

   4. From the Operator option, select an operator that determines how WAF will compare the match value to the request element identified by the above variable.

      Learn more.

   5. In the Match value option, type the value that will be compared against the request element identified by the above variable.

   6. From the Match transformations option, select each transformation that will be applied to the source value.

      Learn more.

   7. Optional. Mark the Negative Match option to match for requests that do not contain a matching value for the value defined in step vi.
8. Optional. Click + Add Condition to add another condition that must be met prior to request identification. Repeat step 7 for this new condition.
9. Optional. Click + Add Rule to add another rule through which WAF may identify requests. Repeat steps 7 and 8.
10. Click Save.

To modify a bot rule set

1. Navigate to the Bot Rules page. How?From the main menu, navigate to More | WAF | WAF Tier | Security Rule Manager | Bot Rules.

2. Click on the desired bot rule set.

3. Make the desired changes.

   Key tasks:

   • Delete variables and matches within a variable by clicking .

   • Delete a condition by clicking Delete Condition.

     A rule must have at least one condition. Therefore, you cannot delete the root condition.

   • Delete a rule by clicking Delete Rule and then clicking Confirm.
4. Click Save.

To delete a bot rule set

1. Navigate to the Bot Rules page. How?From the main menu, navigate to More | WAF | WAF Tier | Security Rule Manager | Bot Rules.

2. Click on the desired bot rule set.
3. Click Delete Bot Rule Profile.
4. Type DELETE.
5. Click Delete.