KMS Key Policy Allows Public Access

What this rule checks

Detects KMS keys whose key policy grants access to a wildcard or public principal.

How to fix it

1. 1Remove wildcard/public principals from the key policy
2. 2Scope key access to specific IAM principals or accounts

import { Key } from 'aws-cdk-lib/aws-kms';
import { PolicyStatement, Effect, AnyPrincipal } from 'aws-cdk-lib/aws-iam';

const key = new Key(this, 'DataKey');
key.addToResourcePolicy(new PolicyStatement({
  effect: Effect.ALLOW,
  principals: [new AnyPrincipal()],
  actions: ['kms:Decrypt', 'kms:GenerateDataKey'],
  resources: ['*'],
}));

import { Key } from 'aws-cdk-lib/aws-kms';
import { Role, ServicePrincipal } from 'aws-cdk-lib/aws-iam';

const role = new Role(this, 'AppServiceRole', { assumedBy: new ServicePrincipal('lambda.amazonaws.com') });
const key = new Key(this, 'DataKey', { enableKeyRotation: true });
key.grantDecrypt(role);

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 kms-key-policy-public and the reason is kept in the report, not silently hidden.

In .cdk-insights.json:

{
  "ignoreRules": [
    { "id": "kms-key-policy-public", "reason": "Why this is intentional" }
  ]
}

Or inline in your CDK code:

Validations.of(scope).acknowledge({
  id: 'cdk-insights::kms-key-policy-public',
  reason: 'Why this is intentional',
});

Use the rule ID kms-key-policy-public 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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