Provisioning and maintenance of EC2 instances (for example, patching, inspecting, creation of snapshots and AMIs, use of EC2 Image Builder)

Describe how you would provision a new EC2 instance and ensure it complies with your company’s security standards.

To provision a new EC2 instance that complies with my company’s security standards, I would follow these steps:

• Select an AMI that has been hardened according to our security policies.
• Utilize EC2 launch templates that include predefined security group settings and IAM roles with least-privilege access.
• Enable monitoring and logging by integrating CloudTrail and CloudWatch.
• Apply necessary tags for resource identification and compliance tracking.
• Automate the provisioning process using tools like AWS CloudFormation or Terraform, including any necessary user-data scripts for initial setup tasks.

How do you automate the patching process for EC2 instances?

To automate the patching process for EC2 instances, I would use AWS Systems Manager Patch Manager to schedule and apply patches according to the defined maintenance window. This service allows for automated patching of operating systems and software, ensuring all instances remain up-to-date with the latest security updates. Systems Manager also allows us to define different patch baselines for different types of instances or environments.

What are some best practices for creating and managing EC2 snapshots?

Best practices for creating and managing EC2 snapshots include:

• Regularly scheduling snapshots using Amazon Data Lifecycle Manager to ensure point-in-time backups.
• Encrypting snapshots to protect data at rest.
• Tagging snapshots for easy identification and management.
• Implementing retention policies to delete old snapshots and optimize storage costs.
• Periodically testing snapshots for recovery to ensure they are reliable.

Explain the difference between EC2 instance snapshots and AMIs. When would you use each?

EC2 instance snapshots are point-in-time backups of EBS volumes, whereas AMIs (Amazon Machine Images) are full copies of EC2 instances, including the instance type, the root volume, and any additional attached EBS volumes. Snapshots are typically used for data backups and restoration of volumes, while AMIs are used for launching new instances or for scaling with identical configurations through Auto Scaling Groups.

What is EC2 Image Builder, and how can it assist with maintaining EC2 instances?

EC2 Image Builder is a service that automates the creation, management, and deployment of customized, secure, and up-to-date “golden” server images. It can assist with maintaining EC2 instances by:

• Enabling automated building and testing of AMIs, ensuring they are patched and configured according to defined standards.
• Streamlining the deployment of updated images across instances.
• Reducing the risk of configuration drift through repeatable image building processes.

What security considerations should you keep in mind when creating AMIs?

When creating AMIs, security considerations should include:

• Pre-installing and configuring security tools such as anti-virus and intrusion detection systems.
• Ensuring no sensitive data is present in the AMI to prevent accidental exposure.
• Enabling encryption for the AMI and associated snapshots to protect the data.
• Following the principle of least privilege when configuring IAM roles to interact with the AMI.

How can you implement a secure method for SSH access to EC2 instances?

Implement a secure method for SSH access by:

• Disabling SSH root login and using SSH keys instead of passwords.
• Using AWS Key Management Service (KMS) to manage SSH keys securely.
• Implementing network controls such as security groups and network ACLs to restrict SSH access to authorized IP addresses.
• Integrating with AWS Identity and Access Management (IAM) for federated SSH access using short-lived credentials.
• Employing AWS Systems Manager Session Manager as an alternative to SSH that doesn’t require open inbound ports and stores session logs for auditing.

What steps would you take to harden a newly provisioned EC2 instance?

To harden a newly provisioned EC2 instance, I would:

• Apply the latest security patches and updates to the operating system and applications.
• Disable unnecessary services and ports to reduce the attack surface.
• Configure host-based firewalls and intrusion detection/prevention systems.
• Set up strict user and file permissions.
• Enforce strong password policies and multi-factor authentication where possible.
• Regularly audit the instance with tools like Amazon Inspector or third-party vulnerability assessment solutions.

How do you manage the lifecycle of EC2 instances securely, particularly when decommissioning?

Managing the lifecycle of EC2 instances securely involves:

• Performing a secure wipe of instance storage to prevent data leakage.
• Taking snapshots and backing up data before decommissioning.
• Revoking IAM roles and access policies associated with the instance.
• Ensuring all associated resources like EIPs, security groups, and volumes are also released or deleted.
• Documenting the decommissioning process for auditing and compliance purposes.

Describe a scenario when you would need to scale your EC2 instances and how you would maintain security during the scaling process.

A scenario for scaling EC2 instances could be a predictable increase in web traffic. During the scaling process, I would maintain security by:

• Using pre-configured AMIs that are regularly updated and vetted for security.
• Employing Auto Scaling Groups with launch configurations that include security group settings and IAM roles to ensure new instances match the desired security posture.
• Enabling CloudTrail and CloudWatch for monitoring and logging purpose.
• Conducting regular post-scaling security checks to ensure compliance with security policies.

Can you explain the importance of tagging EC2 resources and how it relates to security?

Tagging EC2 resources is crucial for:

• Resource identification, which helps with tracking and monitoring resources from a security perspective.
• Cost allocation, to keep tabs on where and how resources are being used, which can uncover unauthorized or non-compliant usage.
• Automating security controls, as tags can trigger Lambda functions or Systems Manager Automation documents for security responses or compliance enforcement.
• Enforcing access control, since tags can be used in IAM policies to fine-tune permissions.

What are some common vulnerabilities associated with EC2 instances, and how would you mitigate them?

Common vulnerabilities associated with EC2 instances include unpatched systems, misconfigured security groups, and inadequate access control. To mitigate these vulnerabilities:

• Regularly apply patches and updates with automated tools like AWS Systems Manager Patch Manager.
• Perform audits and reviews of security group configurations to ensure they follow the principle of least privilege.
• Implement robust IAM policies and roles, use multi-factor authentication, and monitor access patterns with services like CloudTrail and GuardDuty.

Remember that these answers are intended to be brief and to the point. Depending on the interview context, you may need to provide additional details or demonstrate hands-on experience with AWS services and security best practices.