WAF WebACL Misconfigured

What this rule checks

Detects WAFv2 WebACLs with no rules, default Allow action, or CloudWatch metrics disabled.

How to fix it

1. 1Add WAF rules covering the OWASP Top 10 baseline
2. 2Set DefaultAction to Block for defence-in-depth
3. 3Enable CloudWatchMetricsEnabled in VisibilityConfig

import * as wafv2 from 'aws-cdk-lib/aws-wafv2';

// Default action Allow, no rules, metrics disabled.
new wafv2.CfnWebACL(this, 'Acl', {
  scope: 'REGIONAL',
  defaultAction: { allow: {} },
  visibilityConfig: {
    cloudWatchMetricsEnabled: false,
    metricName: 'appAcl',
    sampledRequestsEnabled: false,
  },
});

import * as wafv2 from 'aws-cdk-lib/aws-wafv2';

// Default Block, at least one rule, metrics + sampled requests enabled.
new wafv2.CfnWebACL(this, 'Acl', {
  scope: 'REGIONAL',
  defaultAction: { block: {} },
  visibilityConfig: {
    cloudWatchMetricsEnabled: true,
    metricName: 'appAcl',
    sampledRequestsEnabled: true,
  },
  rules: [
    {
      name: 'AWSCommonRuleSet',
      priority: 1,
      statement: {
        managedRuleGroupStatement: {
          vendorName: 'AWS',
          name: 'AWSManagedRulesCommonRuleSet',
        },
      },
      overrideAction: { none: {} },
      visibilityConfig: {
        cloudWatchMetricsEnabled: true,
        metricName: 'commonRuleSet',
        sampledRequestsEnabled: true,
      },
    },
  ],
});

CDK Insights pinpoints the exact file and line in your CDK source for every finding, so you can jump straight to the fix.

Affected resource types

Intentional? Suppress this finding

Sometimes a flag is deliberate — a genuinely public endpoint, say. You can dismiss waf-webacl-misconfigured and the reason is kept in the report, not silently hidden.

In .cdk-insights.json:

{
  "ignoreRules": [
    { "id": "waf-webacl-misconfigured", "reason": "Why this is intentional" }
  ]
}

Or inline in your CDK code:

Validations.of(scope).acknowledge({
  id: 'cdk-insights::waf-webacl-misconfigured',
  reason: 'Why this is intentional',
});

Use the rule ID waf-webacl-misconfigured shown above — not the CDK-* ID from SARIF / GitHub code scanning. To dismiss every finding on one construct instead, use ignorePaths. Suppression docs →

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