IAM Role Assumable By Any AWS Account

What this rule checks

Detects IAM roles whose trust policy allows a wildcard principal to assume them with no scoping condition — anyone with an AWS account can become the role.

How to fix it

1. 1Name the trusted principals explicitly (account root ARNs, service principals, or federated providers)
2. 2If broad trust is intended, scope it with aws:PrincipalOrgID or an sts:ExternalId condition

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

new iam.CfnRole(this, 'SupportRole', {
  assumeRolePolicyDocument: {
    Version: '2012-10-17',
    Statement: [
      {
        Effect: 'Allow',
        Principal: { AWS: '*' },
        Action: 'sts:AssumeRole',
      },
    ],
  },
});

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

new iam.CfnRole(this, 'SupportRole', {
  assumeRolePolicyDocument: {
    Version: '2012-10-17',
    Statement: [
      {
        Effect: 'Allow',
        Principal: { AWS: 'arn:aws:iam::111122223333:root' },
        Action: 'sts:AssumeRole',
        Condition: { StringEquals: { 'sts:ExternalId': 'support-vendor' } },
      },
    ],
  },
});

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 iam-role-anonymous-assume and the reason is kept in the report, not silently hidden.

In .cdk-insights.json:

{
  "ignoreRules": [
    { "id": "iam-role-anonymous-assume", "reason": "Why this is intentional" }
  ]
}

Or inline in your CDK code:

Validations.of(scope).acknowledge({
  id: 'cdk-insights::iam-role-anonymous-assume',
  reason: 'Why this is intentional',
});

Use the rule ID iam-role-anonymous-assume 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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