Secure remote access methods (for example, SSH, RDP over Systems Manager Session Manager)

What is the primary difference between SSH and RDP when it comes to remote access?

SSH, or Secure Shell, is a protocol primarily used for secure command-line access and file transfers over unsecured networks, typically between a client and a server on Unix-like operating systems. RDP, or Remote Desktop Protocol, is designed for graphical remote desktop connections, mainly on Windows-based systems. SSH encrypts the session to provide confidentiality and integrity, while RDP provides a full graphical user interface experience, which can also be secured using encryption.

How can AWS Systems Manager Session Manager enhance the security of SSH and RDP access?

AWS Systems Manager Session Manager allows administrators to manage servers without the need to open inbound ports, maintain bastion hosts, or manage SSH keys. It provides a browser-based interactive shell and RDP session while logging all session activity to S3 and CloudWatch Logs for auditing, thus enhancing security and simplification of access.

Can you describe the process of setting up an RDP session over AWS Systems Manager Session Manager?

To set up an RDP session over AWS Systems Manager Session Manager, you need to:

• Ensure your instance is managed by AWS Systems Manager with the SSM Agent installed and running.
• Assign an IAM role to the instance with the necessary permissions for Systems Manager.
• Open the AWS Management Console, navigate to Systems Manager, and choose Session Manager.
• Start a new session with the desired instance and choose the ‘Start session’ option.
• Once the command-line session is active, you can port forward the RDP port (3389) and use an RDP client to connect using ‘localhost’.

How can AWS Identity and Access Management (IAM) be used to control who has access to initiate SSH sessions through Systems Manager?

AWS Identity and Access Management (IAM) can be utilized to create policies that specify which users or roles have permission to initiate SSH sessions. Policies can control access by specifying the ‘ssmmessages:CreateControlChannel’ action and other related actions, and attaching them to IAM users, groups, or roles.

What are some best practices for securing an SSH session when using AWS?

Best practices for securing an SSH session in AWS include:

• Use Systems Manager Session Manager for centralized access control and auditability.
• Disable SSH password-based authentication and use key-based authentication.
• Rotate SSH keys regularly.
• Limit access by using security groups and network ACLs.
• Implement Multi-Factor Authentication (MFA).
• Keep the systems and SSH daemon updated with the latest patches.

Why is key rotation important for secure remote access, and how can you enforce it in an AWS environment?

Key rotation is important because it reduces the window of opportunity for an attacker to use a compromised key to gain unauthorized access. In an AWS environment, you can enforce key rotation by setting up an IAM policy that requires users to rotate their SSH keys within a specified time period or using AWS Secrets Manager to automate the rotation of SSH keys.

How does Systems Manager Session Manager log and audit remote access sessions to ensure compliance and security?

Session Manager logs all session activity including command history to Amazon S3 and/or Amazon CloudWatch Logs. This provides an audit trail that can be reviewed for compliance and security analysis. Session Manager also allows you to stream these logs in real-time, which is essential for monitoring and immediate incident response activities.

What are the implications of using a bastion host for SSH access compared to using AWS Systems Manager?

Using a bastion host for SSH access involves managing and securing an additional EC2 instance used as a jump host to access private instances in your VPC. It increases the attack surface and requires keeping the bastion host secure. In comparison, AWS Systems Manager Session Manager eliminates the need for a bastion host, reduces the attack surface, simplifies the management of access keys, and provides centralized logging and audit trails.

Can you explain the role of the SSM Agent when using Systems Manager Session Manager for secure remote access?

The SSM Agent is software that is installed on EC2 instances (or hybrid instances) to enable interaction with AWS Systems Manager. For Session Manager, the agent facilitates the initialization and management of secure sessions to the instance from the AWS Console or CLI, helping to maintain a secure communication channel without the need for open inbound ports or publicly accessible services.

How would you securely manage access to instances in private subnets using Systems Manager Session Manager and VPC endpoints?

To manage access securely, you would:

• Install and configure the SSM Agent on the instances to make them Systems Manager managed.
• Set up an IAM policy to define who can access the instances through Session Manager.
• Create a VPC endpoint for Systems Manager to ensure that all traffic between the VPC and Systems Manager stays within the AWS network, enhancing security by not traversing the public internet.
• Use Session Manager to access the instances securely without the need for a public IP address or inbound security group rules.