KMS Key Policy Self-Lockout

What this rule checks

Detects AWS::KMS::Key resources whose KeyPolicy contains a Deny statement on kms:*, kms:PutKeyPolicy, or * with a broad Principal and no carveout for the account root or admin role. Such a policy locks the account out of its own key — recovery requires breaking glass on the account root credentials AND scheduling a 7-30 day key deletion (which does not actually let you recover the key, just remove it). Effectively unrecoverable for any data the key has encrypted; AWS Support typically declines to intervene where customers have a self-service path via root.

How to fix it

1. 1Keep the auto-injected root Allow statement (CDK's defaultKeyPolicy) intact, or add an explicit Allow on Principal: { AWS: 'arn:aws:iam::<account>:root' } for Action: kms:*
2. 2Or add a NotPrincipal exemption for the account root or admin role(s)
3. 3Or use a Condition with StringNotEquals on aws:PrincipalArn to exempt admin role ARNs

import { aws_kms as kms } from 'aws-cdk-lib';

new kms.CfnKey(this, 'Key', {
  keyPolicy: {
    Version: '2012-10-17',
    Statement: [
      { Effect: 'Deny', Principal: '*', Action: 'kms:*', Resource: '*' },
    ],
  },
});

import { Aws, aws_kms as kms } from 'aws-cdk-lib';

new kms.CfnKey(this, 'Key', {
  keyPolicy: {
    Version: '2012-10-17',
    Statement: [
      {
        Sid: 'EnableRootAccess',
        Effect: 'Allow',
        Principal: { AWS: `arn:aws:iam::${Aws.ACCOUNT_ID}:root` },
        Action: 'kms:*',
        Resource: '*',
      },
      {
        Sid: 'DenyEveryoneButRoot',
        Effect: 'Deny',
        NotPrincipal: { AWS: `arn:aws:iam::${Aws.ACCOUNT_ID}:root` },
        Action: 'kms:*',
        Resource: '*',
      },
    ],
  },
});

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-self-lockout and the reason is kept in the report, not silently hidden.

In .cdk-insights.json:

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

Or inline in your CDK code:

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

Use the rule ID kms-key-policy-self-lockout 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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