SEC08-BP04: Enforce access control

Overview

Enforcing access control for data at rest ensures that only authorized users and systems can access stored data, regardless of the underlying storage mechanism. This best practice focuses on implementing comprehensive access control mechanisms that work in conjunction with encryption to provide defense-in-depth protection for sensitive data.

Access control should be implemented at multiple layers including identity-based controls, resource-based policies, network-level restrictions, and application-level authorization. The controls should be based on the principle of least privilege and support both human and programmatic access patterns.

Implementation Guidance

1. Implement Identity-Based Access Control

Deploy comprehensive identity and access management:

AWS IAM Policies: Fine-grained permissions for users, groups, and roles
Attribute-Based Access Control (ABAC): Dynamic access control based on attributes
Multi-Factor Authentication: Additional authentication factors for sensitive data access
Temporary Credentials: Time-limited access using AWS STS

2. Configure Resource-Based Access Control

Implement resource-specific access policies:

S3 Bucket Policies: Control access to objects and buckets
KMS Key Policies: Control encryption key usage and management
RDS Resource Policies: Database-level access control
Cross-Account Access: Secure sharing across AWS accounts

3. Deploy Network-Level Access Control

Establish network-based access restrictions:

VPC Endpoints: Private connectivity to AWS services
Security Groups: Instance-level firewall rules
Network ACLs: Subnet-level network filtering
AWS PrivateLink: Private connectivity for service access

4. Implement Application-Level Authorization

Deploy application-specific access controls:

Database Permissions: Row-level and column-level security
Application Roles: Role-based access within applications
API Gateway Authorization: Control access to data APIs
Lambda Authorizers: Custom authorization logic

5. Enable Continuous Access Monitoring

Implement comprehensive access monitoring:

CloudTrail Logging: Complete audit trail of access attempts
VPC Flow Logs: Network-level access monitoring
Application Logs: Application-specific access logging
Real-Time Alerting: Immediate notification of unauthorized access

6. Establish Access Control Governance

Deploy governance mechanisms for access control:

Access Reviews: Regular review of access permissions
Automated Provisioning: Consistent access provisioning processes
Access Certification: Periodic validation of access requirements
Compliance Reporting: Regular access control compliance reports

Implementation Examples

Example 1: Comprehensive Access Control Management System

Example 2: Attribute-Based Access Control (ABAC) Implementation

Example 3: CloudFormation Template for Comprehensive Access Control

Relevant AWS Services

Identity and Access Management

AWS Identity and Access Management (IAM): Fine-grained access control policies and roles
AWS Single Sign-On (SSO): Centralized access management across AWS accounts
Amazon Cognito: User authentication and authorization for applications
AWS Security Token Service (STS): Temporary credential generation

Network Access Control

Amazon VPC: Network isolation and security groups
AWS PrivateLink: Private connectivity to AWS services
VPC Endpoints: Secure access to AWS services without internet gateway
AWS Direct Connect: Dedicated network connection to AWS

Resource-Based Access Control

Amazon S3: Bucket policies and access control lists
AWS Key Management Service (KMS): Key policies for encryption access control
Amazon RDS: Database-level access control and resource policies
AWS Lambda: Function-level access control and resource policies

Monitoring and Auditing

AWS CloudTrail: Comprehensive audit logging of access attempts
Amazon CloudWatch: Monitoring and alerting for access patterns
VPC Flow Logs: Network-level access monitoring
AWS Config: Configuration compliance monitoring

Automation and Governance

AWS Organizations: Service Control Policies for organization-wide access control
AWS Control Tower: Automated governance and compliance
AWS Systems Manager: Automated access provisioning and management
Amazon EventBridge: Event-driven access control workflows

Benefits of Enforcing Access Control

Security Benefits

Defense in Depth: Multiple layers of access control protection
Principle of Least Privilege: Minimal necessary access permissions
Dynamic Access Control: Context-aware access decisions
Comprehensive Auditing: Complete visibility into access patterns

Operational Benefits

Automated Provisioning: Consistent access control implementation
Centralized Management: Single point of control for access policies
Scalable Architecture: Access control that grows with infrastructure
Reduced Administrative Overhead: Automated access management

Compliance Benefits

Regulatory Adherence: Meet compliance requirements for data access
Audit Readiness: Complete audit trails for access control
Policy Enforcement: Consistent enforcement of access policies
Risk Management: Controlled access to sensitive data

Business Benefits

Data Protection: Safeguard valuable business data assets
Operational Continuity: Secure access without business disruption
Cost Optimization: Efficient access control resource utilization
Competitive Advantage: Secure data handling as business differentiator