Recent investigations have unveiled critical vulnerabilities within Amazon Web Services (AWS) default Identity and Access Management (IAM) roles. These roles, often automatically generated or recommended during service setup, grant excessively broad permissions, notably full access to Amazon S3 buckets. Such configurations inadvertently create pathways for attackers to escalate privileges, manipulate various AWS services, and potentially compromise entire AWS accounts.
Understanding the Vulnerabilities
AWS services like SageMaker, Glue, and EMR, along with open-source projects such as Ray, commonly create default IAM roles during their initialization. These roles are intended to streamline the setup process for users. However, the permissions associated with these roles are often overly permissive. For instance:
– Amazon SageMaker: Upon setting up a SageMaker Domain, a default execution role named `AmazonSageMaker-ExecutionRole-
– AWS Glue: The service generates a default role called `AWSGlueServiceRole`, which is attached to the `AmazonS3FullAccess` policy, allowing comprehensive access to S3 resources.
– Amazon EMR: During setup, a default role named `AmazonEMRStudio_RuntimeRole_
– Ray: This open-source framework automatically creates a default IAM role (`ray-autoscaler-v1`) with the `AmazonS3FullAccess` policy, granting extensive S3 permissions.
The primary concern with these configurations is that while the roles are designed for specific service functionalities, their broad permissions can be exploited. An attacker who gains access to such a role can perform administrative actions beyond the intended scope, effectively breaking isolation boundaries between services. This capability allows for lateral movement across services within the same AWS account, escalating privileges, and potentially leading to full account compromise.
Potential Attack Scenarios
Consider a scenario where an attacker uploads a malicious machine learning model to a platform like Hugging Face. When this model is imported into SageMaker, it could execute arbitrary code. Given the default role’s extensive permissions, the attacker could:
1. Access Other AWS Services: Utilize the compromised SageMaker role to interact with other services like AWS Glue.
2. Inject Malicious Code: Modify Glue scripts or CloudFormation templates stored in S3 buckets to include backdoors or other malicious payloads.
3. Steal Credentials: Extract IAM credentials from compromised services, facilitating further exploitation.
4. Escalate Privileges: Leverage the compromised roles to gain higher-level access within the AWS environment.
Such an attack chain underscores the risks associated with overly permissive default IAM roles, highlighting the need for stringent access controls and regular audits.
AWS’s Response and Recommendations
In response to these findings, AWS has taken steps to mitigate the risks associated with default IAM roles:
– Policy Adjustments: AWS has modified the `AmazonS3FullAccess` policy for default service roles, narrowing the scope of permissions to align more closely with the principle of least privilege.
– Documentation Updates: AWS has updated its documentation to provide clearer guidance on IAM role configurations, emphasizing the importance of restricting permissions to only those necessary for specific tasks.
– Customer Notifications: AWS has proactively notified affected customers about the changes and provided recommendations for securing their environments.
Despite these efforts, organizations must take proactive measures to secure their AWS environments:
1. Audit IAM Roles: Regularly review all IAM roles to identify and remediate overly permissive policies.
2. Implement Least Privilege: Ensure that IAM roles are granted only the permissions necessary for their specific functions, avoiding broad policies like `AmazonS3FullAccess` unless absolutely required.
3. Monitor for Unused Roles: Identify and remove or restrict IAM roles that are no longer in use to reduce the attack surface.
4. Restrict S3 Access: Limit S3 permissions to specific buckets and actions required by the service, avoiding wildcard permissions that grant unrestricted access.
5. Enhance Logging and Monitoring: Utilize AWS CloudTrail and other monitoring tools to detect and respond to unauthorized activities promptly.
Conclusion
The discovery of vulnerabilities in AWS default IAM roles serves as a critical reminder of the importance of secure configurations in cloud environments. While default settings are designed for ease of use, they can inadvertently introduce significant security risks. Organizations must adopt a proactive approach to IAM management, ensuring that roles are configured with the minimum necessary permissions and are regularly audited to prevent potential exploitation.
