Blocking requests that don't have a valid AWS WAF token

This section explains how to block login requests that are missing their tokens when using the AWS WAF mobile SDK.

When you use the intelligent threat AWS Managed Rules rule groups AWSManagedRulesACFPRuleSet, AWSManagedRulesATPRuleSet, and AWSManagedRulesBotControlRuleSet, the rule groups invoke AWS WAF token management to evaluate the status of the web request token and to label the requests accordingly.

Note

Token labeling is only applied to web requests that you evaluate using one of these managed rule groups.

For information about the labeling that token management applies, see the preceding section, Types of token labels in AWS WAF.

The intelligent threat mitigation managed rule groups then handle token requirements as follows:

• The AWSManagedRulesACFPRuleSet AllRequests rule is configured to run the Challenge action against all requests, effectively blocking any that don't have the accepted token label.

• The AWSManagedRulesATPRuleSet blocks requests that have the rejected token label, but it doesn't block requests with the absent token label.

• The AWSManagedRulesBotControlRuleSet targeted protection level challenges clients after they send five requests without an accepted token label. It doesn't block an individual request that doesn't have a valid token. The common protection level of the rule group doesn't manage token requirements.

For additional details about the intelligent threat rule groups, see AWS WAF Fraud Control account creation fraud prevention (ACFP) rule group, AWS WAF Fraud Control account takeover prevention (ATP) rule group and AWS WAF Bot Control rule group.

To block requests that are missing tokens when using the Bot Control or ATP managed rule group

With the Bot Control and ATP rule groups, it's possible for a request without a valid token to exit the rule group evaluation and continue to be evaluated by the web ACL.

To block all requests that are missing their token or whose token is rejected, add a rule to run immediately after the managed rule group to capture and block requests that the rule group doesn't handle for you.

The following is an example JSON listing for a web ACL that uses the ATP managed rule group. The web ACL has an added rule to capture the awswaf:managed:token:absent label and handle it. The rule narrows its evaluation to web requests going to the login endpoint, to match the scope of the ATP rule group. The added rule is listed in bold.

{
  "Name": "exampleWebACL",
  "Id": "55555555-6666-7777-8888-999999999999",
  "ARN": "arn:aws:wafv2:us-east-1:111111111111:regional/webacl/exampleWebACL/55555555-4444-3333-2222-111111111111",
  "DefaultAction": {
    "Allow": {}
  },
  "Description": "",
  "Rules": [
    {
      "Name": "AWS-AWSManagedRulesATPRuleSet",
      "Priority": 1,
      "Statement": {
        "ManagedRuleGroupStatement": {
          "VendorName": "AWS",
          "Name": "AWSManagedRulesATPRuleSet",
          "ManagedRuleGroupConfigs": [
            {
              "AWSManagedRulesATPRuleSet": {
                "LoginPath": "/web/login",
                "RequestInspection": {
                  "PayloadType": "JSON",
                  "UsernameField": {
                    "Identifier": "/form/username"
                  },
                  "PasswordField": {
                    "Identifier": "/form/password"
                  }
                },
                "ResponseInspection": {
                  "StatusCode": {
                    "SuccessCodes": [
                      200
                    ],
                    "FailureCodes": [
                      401,
                      403,
                      500
                    ]
                  }
                }
              }  
            }
          ]
        }
      },
      "OverrideAction": {
        "None": {}
      },
      "VisibilityConfig": {
        "SampledRequestsEnabled": true,
        "CloudWatchMetricsEnabled": true,
        "MetricName": "AWS-AWSManagedRulesATPRuleSet"
      }
    },
    {
      "Name": "RequireTokenForLogins",
      "Priority": 2,
      "Statement": {
        "AndStatement": {
          "Statements": [
            {
              "Statement": {
                "LabelMatchStatement": {
                  "Scope": "LABEL",
                  "Key": "awswaf:managed:token:absent"
                }
              }
            },
            {
              "ByteMatchStatement": {
                "SearchString": "/web/login",
                "FieldToMatch": {
                  "UriPath": {}
                },
                "TextTransformations": [
                  {
                    "Priority": 0,
                    "Type": "NONE"
                 }
                ],
                "PositionalConstraint": "STARTS_WITH"
              }
            },
            {
              "ByteMatchStatement": {
                "SearchString": "POST",
                "FieldToMatch": {
                  "Method": {}
                },
                "TextTransformations": [
                  {
                    "Priority": 0,
                    "Type": "NONE"
                  }
                ],
                "PositionalConstraint": "EXACTLY"
              }
            }
          ]
        }
      },
      "Action": {
        "Block": {}
      },
      "VisibilityConfig": {
        "SampledRequestsEnabled": true,
        "CloudWatchMetricsEnabled": true,
        "MetricName": "RequireTokenForLogins"
      } 
    }
  ],
  "VisibilityConfig": {
    "SampledRequestsEnabled": true,
    "CloudWatchMetricsEnabled": true,
    "MetricName": "exampleWebACL"
  },
  "Capacity": 51,
  "ManagedByFirewallManager": false,
  "RetrofittedByFirewallManager": false,
  "LabelNamespace": "awswaf:111111111111:webacl:exampleWebACL:"
}