1. Introduction
Amazon Cognito Insecure Permissions relate to misconfigured access controls within Amazon’s cloud authentication service. This allows unauthenticated users to retrieve temporary AWS credentials, potentially granting them access to sensitive resources and data. Affected systems are typically web and mobile applications using Amazon Cognito for user management. A successful exploit could compromise the confidentiality, integrity, and availability of associated AWS account assets.
2. Technical Explanation
The root cause is overly permissive policies attached to Cognito identity pools. When configured with an identity pool ID, Cognito allows unauthenticated users to obtain temporary credentials. If these credentials have excessive permissions, attackers can access resources they shouldn’t be able to reach. An attacker could exploit this by retrieving the credentials and using them to list S3 buckets, read data from databases, or modify other cloud infrastructure.
- Root cause: Excessive IAM permissions granted to Cognito roles.
- Exploit mechanism: An unauthenticated user requests temporary AWS credentials via the Cognito service. These credentials are then used to interact with AWS resources based on the attached policy.
- Scope: Applications using Amazon Cognito identity pools with misconfigured IAM policies.
3. Detection and Assessment
To confirm vulnerability, review the permissions associated with your Cognito identity pools. Start with a quick check of role policies, then perform a thorough audit to identify overly permissive settings.
- Quick checks: In the AWS Management Console, navigate to Cognito > Identity Pools and examine the IAM roles attached to each pool.
- Scanning: CloudSploit and other cloud security posture management (CSPM) tools may flag excessive permissions on Cognito roles. These are examples only.
- Logs and evidence: Review AWS CloudTrail logs for requests to assume-role with associated identity pool IDs. Look for unexpected or unauthorized access attempts.
aws iam get-role --role-name 4. Solution / Remediation Steps
Fix the issue by reviewing and restricting permissions on Cognito role policies to follow the principle of least privilege.
4.1 Preparation
- No services need to be stopped for this remediation.
- Roll back plan: Revert the IAM policy to its previous state if issues arise. Change approval may be required depending on internal policies.
4.2 Implementation
- Step 1: Identify all Cognito identity pools in your AWS account.
- Step 2: For each pool, review the attached IAM role’s policy.
- Step 3: Modify the policy to grant only the minimum necessary permissions required for the application’s functionality. Remove any wildcard (*) or broad access grants.
4.3 Config or Code Example
Before
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": "*",
"Resource": "*"
}
]
}After
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"s3:GetObject",
"s3:PutObject"
],
"Resource": "arn:aws:s3:::your-bucket/*"
}
]
}4.4 Security Practices Relevant to This Vulnerability
Several security practices can help prevent this issue. Least privilege is key, as is regular review of IAM policies.
- Practice 1: Implement the principle of least privilege when configuring IAM roles and policies. Grant only the minimum permissions required for each application or service.
- Practice 2: Regularly audit IAM policies to identify and remove excessive permissions. Automate this process where possible.
4.5 Automation (Optional)
Infrastructure-as-code tools can automate policy enforcement.
# Example Terraform snippet (ensure proper AWS provider configuration)
resource "aws_iam_role_policy" "cognito_role_policy" {
name = "CognitoRolePolicy"
role = aws_iam_role.cognito_role.name
policy = jsonencode({
Version = "2012-10-17",
Statement = [
{
Effect = "Allow",
Action = ["s3:GetObject"],
Resource = "arn:aws:s3:::your-bucket/*"
}
]
})
}5. Verification / Validation
Confirm the fix by verifying that IAM policies are restricted and testing application functionality.
- Post-fix check: Run `aws iam get-role –role-name
` and confirm the policy only allows necessary actions on specific resources. - Re-test: Re-run the IAM role policy review to ensure no excessive permissions remain.
- Smoke test: Verify that users can still authenticate and access core application features.
- Monitoring: Monitor AWS CloudTrail logs for any unauthorized access attempts using Cognito credentials. Look for actions outside of the permitted scope.
aws iam get-role --role-name 6. Preventive Measures and Monitoring
Update security baselines to include least privilege IAM policy requirements. Implement CI/CD pipeline checks for overly permissive policies.
- Baselines: Update your AWS security baseline or CIS benchmark to enforce the principle of least privilege for Cognito roles.
- Asset and patch process: Review IAM role configurations regularly as part of a security asset management program, at least quarterly.
7. Risks, Side Effects, and Roll Back
- Risk or side effect 1: Application features may stop working if necessary permissions are removed.
- Risk or side effect 2: Users may experience errors when accessing resources they previously had access to.
8. References and Resources
- Vendor advisory or bulletin: https://aws.amazon.com/cognito/
- NVD or CVE entry: No specific CVE is listed for this general configuration issue.
- Product or platform documentation relevant to the fix: https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_create_role-cognito.html