Analyze public and cross-account access

Effectively managing permissions is crucial for safeguarding AWS workloads. Regularly analyzing public and cross-account access ensures that permissions are aligned with the principle of least privilege, helping to mitigate security risks associated with excessive access rights.

Best Practices

Regularly Audit IAM Policies and Permissions

• Conduct regular audits of AWS Identity and Access Management (IAM) policies to ensure that only required permissions are granted. This helps minimize the risk of excessive permissions and potential security breaches.
• Use IAM Access Analyzer to identify and analyze public and cross-account access points within your AWS accounts, making it easier to spot unintended access.
• Implement least privilege access by reviewing and updating IAM policies to remove unnecessary permissions.
• Track changes and access granted over time to enhance visibility and accountability in permission management.

Employ Resource-Based Policies for Granular Control

• Utilize resource-based policies (e.g., S3 bucket policies, SNS topic policies) to control access at the resource level. This allows you to provide access only to specific resources that require exposure to public or cross-account access.
• Set conditions in your policies to restrict access based on factors such as source IP, time of day, or request origin.
• Regularly evaluate and adjust these policies to ensure they align with evolving security needs and workloads.

Monitor Public and Cross-Account Access Continuously

• Implement AWS CloudTrail to log and monitor API calls across your AWS environment. This ensures that you have visibility into who’s accessing resources and the actions they’re taking.
• Set up Amazon CloudWatch alarms to alert your team of any unauthorized access attempts or changes in resource access configurations.
• Utilize AWS Config to enable resource monitoring and evaluation against defined best practices, aiding in the early detection of misconfigurations or policy violations.

Educate and Train Your Team on Security Best Practices

• Provide training sessions on IAM best practices and the importance of managing permissions to avoid security incidents.
• Create documentation and guidelines for developers and administrators on how to correctly request, grant, and analyze permissions.
• Establish a culture of security awareness, helping employees understand their role in protecting access to AWS resources.

Questions to ask your team

• What mechanisms are in place to regularly review and adjust public and cross-account access permissions?
• How do you identify resources that have excessive public access?
• What processes do you follow to ensure that cross-account access is limited to only necessary accounts?
• How often do you conduct audits of permissions for people and machines?
• What tools do you use to automatically monitor and alert for changes in public and cross-account permissions?
• Can you provide examples of how you have minimized public and cross-account access in the past?
• How do you ensure compliance with your organization’s security policies regarding access management?

Who should be doing this?

Cloud Security Architect

• Design and implement secure access controls for AWS resources.
• Define and enforce policies for public and cross-account access.
• Regularly review public and cross-account access permissions.
• Collaborate with development teams to ensure secure coding practices are followed.

AWS Administrator

• Manage and configure IAM policies and roles.
• Perform regular audits of permissions for users and machines.
• Monitor for unauthorized access or changes to permissions.
• Implement changes to reduce public and cross-account access where necessary.

Compliance Officer

• Ensure that access management complies with organizational and regulatory standards.
• Conduct audits and produce reports on access permissions.
• Review findings from security assessments related to permissions.

DevOps Engineer

• Implement CI/CD practices that respect permissions and access controls.
• Set up monitoring and alerts for public and cross-account access configurations.
• Work with the security team to develop automated tools for reducing undesired access.

What evidence shows this is happening in your organization?

• Public Access Review Checklist: A checklist that outlines steps for reviewing and assessing public access settings across AWS services. It includes guidelines for identifying unnecessary public access and how to remediate those findings.
• Cross-Account Access Policy Template: A template for creating policies that restrict cross-account access. This template helps define the necessary permissions while limiting access to only the required AWS resources for external accounts.
• Access Monitoring Dashboard: A real-time monitoring dashboard configured in AWS CloudWatch that tracks public and cross-account access findings. It visualizes access patterns and highlights anomalies for quick remediation.
• Access Control Strategy Document: A comprehensive document outlining the organization’s strategy for managing permissions for users and machines. It includes best practices for minimizing public and cross-account access.
• Security Incident Response Playbook: A playbook detailing the steps to take when a security incident is detected related to unauthorized public or cross-account access. It outlines roles, responsibilities, and communication procedures.

Cloud Services

AWS

• AWS Identity and Access Management (IAM): IAM allows you to manage access to AWS services and resources securely. Create roles and policies to enforce the principle of least privilege and monitor permissions.
• AWS CloudTrail: CloudTrail provides visibility into user activity and API usage across your AWS account, which is critical for identifying unauthorized access and cross-account access.
• Amazon GuardDuty: GuardDuty is a threat detection service that continuously monitors for malicious activity and unauthorized behavior to help protect your AWS accounts and workloads.
• AWS Config: AWS Config provides a detailed view of the configuration of AWS resources in your account, including access policies, helping you track changes in permissions.

Azure

• Azure Active Directory (AAD): AAD helps manage user identities and permissions, enabling secure access to Azure services, application resources, and ensuring compliance.
• Azure Monitor: Azure Monitor offers a range of monitoring tools that help track access and activity, making it easier to identify unusual patterns in cross-account access.

Google Cloud Platform

• Google Cloud Identity: Cloud Identity helps manage user identities and policies, enabling effective control over who has access to your GCP resources.
• Cloud Security Command Center: This service provides security visibility and helps you prevent, detect, and respond to threats across your Google Cloud services, including monitoring access and permissions.

Question: How do you manage permissions for people and machines?
Pillar: Security (Code: SEC)