Configure HTTP DDoS Attack Protection via API

Configure the HTTP DDoS Attack Protection managed ruleset by defining overrides using the Rulesets API.

Each zone has the HTTP DDoS Attack Protection managed ruleset enabled by default. This means that you do not need to deploy the managed ruleset to the ddos_l7 phase ruleset explicitly. You only have to create a rule in the phase ruleset to deploy the managed ruleset if you need to configure overrides.

​​ Configure an override for the HTTP DDoS Attack Protection managed ruleset

Use overrides to configure the HTTP DDoS Attack Protection managed ruleset. Overrides allow you to define a different action or sensitivity level from the default values. For more information on the available action and sensitivity level values, refer to Ruleset parameters.

Overrides can have a ruleset, tag, or rule scope. Tag and rule configurations have greater priority than ruleset configurations.

You can create overrides at the zone level and at the account level. Account-level overrides allow you to apply the same override to several zones in your account with a single rule. For example, you can use an account-level override to lower the sensitivity of a specific managed ruleset rule or exclude an IP List for multiple zones. However, if a given zone has overrides for the HTTP DDoS Attack Protection managed ruleset, the account-level overrides will not be applied for that zone.

​​ Creating multiple rules

Create multiple rules in the ddos_l7 phase entry point ruleset to define different overrides for different sets of incoming requests. Set each rule expression according to the traffic whose HTTP DDoS protection you wish to customize.

Rules in the phase entry point ruleset, where you create overrides, are evaluated in order until there is a match for a rule expression and sensitivity level. Therefore, the rule order in the entry point ruleset is very important: a rule with a higher sensitivity level must come after a rule with a lower sensitivity level, otherwise it will never be evaluated.

​​ Example API calls

​​ Zone-level configuration example

The following PUT example creates a new phase ruleset (or updates the existing one) for the ddos_l7 phase at the zone level. The request includes several overrides to adjust the default behavior of the HTTP DDoS Attack Protection managed ruleset. These overrides are the following:

• All rules of the managed ruleset will use the managed_challenge action and have a sensitivity level of medium.
• All rules tagged with <TAG_NAME> will have a sensitivity level of low.
• The rule with ID <MANAGED_RULESET_RULE_ID> will use the block action.

Request
curl --request PUT \
https://api.cloudflare.com/client/v4/zones/{zone_id}/rulesets/phases/ddos_l7/entrypoint \
--header "Authorization: Bearer <API_TOKEN>" \
--header "Content-Type: application/json" \
--data '{
  "description": "Execute HTTP DDoS Attack Protection managed ruleset in the zone-level phase entry point ruleset",
  "rules": [
    {
      "action": "execute",
      "action_parameters": {
        "id": "<MANAGED_RULESET_ID>",
        "overrides": {
          "sensitivity_level": "medium",
          "action": "managed_challenge",
          "categories": [
            {
              "category": "<TAG_NAME>",
              "sensitivity_level": "low"
            }
          ],
          "rules": [
            {
              "id": "<MANAGED_RULESET_RULE_ID>",
              "action": "block"
            }
          ]
        }
      },
      "expression": "true"
    }
  ]
}'

The response returns the created (or updated) phase entry point ruleset.

{
  "result": {
    "id": "<PHASE_ENTRY_POINT_RULESET_ID>",
    "name": "default",
    "description": "Execute HTTP DDoS Attack Protection managed ruleset in the zone-level phase entry point ruleset",
    "kind": "zone",
    "version": "1",
    "rules": [
      {
        "id": "<RULE_ID>",
        "version": "1",
        "action": "execute",
        "action_parameters": {
          "id": "<MANAGED_RULESET_ID>",
          "version": "latest",
          "overrides": {
            "action": "managed_challenge",
            "categories": [
              {
                "category": "<TAG_NAME>",
                "sensitivity_level": "low"
              }
            ],
            "rules": [
              {
                "id": "<MANAGED_RULESET_RULE_ID>",
                "action": "block"
              }
            ],
            "sensitivity_level": "medium"
          }
        },
        "expression": "true",
        "last_updated": "2021-06-16T04:14:47.977741Z",
        "ref": "<RULE_REF>",
        "enabled": true
      }
    ],
    "last_updated": "2021-06-16T04:14:47.977741Z",
    "phase": "ddos_l7"
  }
}

For more information on defining overrides for managed rulesets using the Rulesets API, refer to Override a managed ruleset in the Ruleset Engine documentation.

​​ Account-level configuration example

The following PUT example creates a new phase ruleset (or updates the existing one) for the ddos_l7 phase at the account level. The example defines a single rule override for requests coming from IP addresses in the allowlisted_ips IP List, with the following configuration:

• The rule with ID <MANAGED_RULESET_RULE_ID>, belonging to the HTTP DDoS Attack Protection managed ruleset (with ID <MANAGED_RULESET_ID>), will have an eoff (Essentially Off) sensitivity level and it will perform a log action.

Request
curl --request PUT \
https://api.cloudflare.com/client/v4/accounts/{account_id}/rulesets/phases/ddos_l7/entrypoint \
--header "Authorization: Bearer <API_TOKEN>" \
--header "Content-Type: application/json" \
--data '{
  "description": "Disable a managed ruleset rule for allowlisted IP addresses",
  "rules": [
    {
      "expression": "ip.src in $allowlisted_ips",
      "action": "execute",
      "action_parameters": {
        "id": "<MANAGED_RULESET_ID>",
        "overrides": {
          "rules": [
            {
              "id": "<MANAGED_RULESET_RULE_ID>",
              "action": "log",
              "sensitivity_level": "eoff"
            }
          ]
        }
      }
    }
  ]
}'

The response returns the created (or updated) phase entry point ruleset.

{
  "result": {
    "id": "<PHASE_ENTRY_POINT_RULESET_ID>",
    "name": "default",
    "description": "Disable a managed ruleset rule for allowlisted IP addresses",
    "kind": "root",
    "version": "1",
    "rules": [
      {
        "id": "<RULE_ID>",
        "version": "1",
        "action": "execute",
        "action_parameters": {
          "id": "<MANAGED_RULESET_ID>",
          "version": "latest",
          "overrides": {
            "rules": [
              {
                "id": "<MANAGED_RULESET_RULE_ID>",
                "action": "log",
                "sensitivity_level": "eoff"
              }
            ],
          }
        },
        "expression": "ip.src in $allowlisted_ips",
        "last_updated": "2022-10-16T04:14:47.977741Z",
        "ref": "<RULE_REF>",
        "enabled": true
      }
    ],
    "last_updated": "2022-10-16T04:14:47.977741Z",
    "phase": "ddos_l7"
  }
}

For more information on defining overrides for managed rulesets using the Rulesets API, refer to Override a managed ruleset in the Ruleset Engine documentation.