Analyze public and cross-account access

Continuously analyzing public and cross-account access to your AWS resources helps ensure that only the necessary entities have access to specific resources, minimizing security risks. By reducing public and cross-account access to only what is absolutely required, you protect your cloud environment from unintended exposure or unauthorized access.

1. Monitor public and cross-account access: Use tools such as AWS IAM Access Analyzer and AWS Config to continuously monitor for resources that are publicly accessible or shared across accounts. This monitoring helps you detect any unintended access or potential vulnerabilities.
2. Identify and reduce public access: Regularly review all resources exposed to the public internet. Where possible, remove public access to resources like S3 buckets, databases, or EC2 instances, and restrict access to only specific trusted accounts or networks. Ensure that public access is only enabled for resources where it is explicitly required.
3. Manage cross-account access: For resources that need to be shared across AWS accounts, ensure that cross-account access is tightly controlled. Use IAM policies and resource-based policies to specify which accounts or entities are allowed access, applying the least privilege principle to restrict access to the necessary resources.
4. Use AWS IAM Access Analyzer: Leverage IAM Access Analyzer to automatically detect resources with public or cross-account access. This tool helps you quickly identify potential security risks and take action to reduce unnecessary exposure.
5. Audit and review access policies regularly: Perform regular audits of public and cross-account access policies to ensure they align with current security best practices. Remove or tighten access when it is no longer needed, and ensure that access remains scoped appropriately.
6. Implement resource tagging for visibility: Tag resources that are exposed to the public or shared across accounts to provide clear visibility into their access status. Tags can help track and review access permissions and ensure that public and cross-account resources are carefully managed.

Supporting Questions:

• How do you continuously monitor and review public and cross-account access to your AWS resources?
• What processes are in place to reduce unnecessary public and cross-account access?
• How do you manage and enforce least privilege for resources that require cross-account access?

Roles and Responsibilities:

Cloud Security Architect:

• Responsibilities:
  • Design and implement strategies to minimize public and cross-account access, ensuring that resources are only accessible by authorized entities.
  • Use AWS IAM Access Analyzer to continuously monitor for public and cross-account access risks.
  • Review and update access policies regularly to remove unnecessary or excessive access.

Cloud Administrator:

• Responsibilities:
  • Manage and configure cross-account access using IAM and resource-based policies to restrict access to specific resources.
  • Monitor and log access using AWS tools to detect public exposure or unauthorized cross-account sharing.
  • Work with the security team to reduce public access and enforce access controls based on current organizational needs.

Artefacts:

• Access Control Policies: Documentation outlining the public and cross-account access policies for each resource, including how access is managed and restricted.
• Access Analyzer Reports: Reports generated by AWS IAM Access Analyzer showing resources with public or cross-account access and recommendations for reducing exposure.
• Audit Logs: Logs from AWS CloudTrail or AWS Config that track access to resources and identify any anomalies or unauthorized access patterns.

Relevant AWS Services:

AWS Identity Services:

• AWS Identity and Access Management (IAM): Use IAM policies to control cross-account access and resource-based policies to restrict public access, ensuring least privilege is applied.
• AWS IAM Access Analyzer: A tool that helps detect resources with public or cross-account access and provides recommendations to reduce unnecessary exposure.

Monitoring and Compliance Services:

• AWS CloudTrail: Logs all access events for resources, enabling you to monitor public and cross-account access patterns and detect potential security risks.
• AWS Config: Tracks configuration changes to resources, including updates to public and cross-account access policies, ensuring compliance with your security requirements.