Use backups to recover from security incidents

Greetings from the AWS Customer Incident Response Team (CIRT)! AWS CIRT is dedicated to supporting customers during active security events on the customer side of the AWS Shared Responsibility Model.

Over the past three years, AWS CIRT has supported customers with security events in their AWS accounts. These include the unauthorized use of AWS Identity and Access Management (IAM) credentials, ransomware, and data deletion in an AWS account.

In this post, I will walk you through key AWS services and features that provide backup and recovery solutions to restore your data based upon the lessons our team has learned when supporting customers experiencing security events.

Shared Responsibility Model

Security is a shared responsibility between AWS and the customer. Customers are responsible for protecting their data IN the cloud. For Amazon Elastic Compute Cloud (Amazon EC2), this includes the guest operating system, installed applications, and data stored within the instance and associated Amazon Elastic Block Store (Amazon EBS) volumes. For Amazon Simple Storage Service (Amazon S3) and Amazon DynamoDB, AWS operates the infrastructure layer, the operating system, and service resources, and customers access the endpoints to store and retrieve data.

Backup and recovery configuration are a part of the customer’s side of the shared responsibility model. AWS doesn’t have the ability to recover a deleted resource. It doesn’t matter how quickly the event is reported to AWS. The inability to recover resources includes actions by the AWS account root user or an IAM principal in the account.

Customers are also responsible for managing their data (including encryption options), classifying their assets, and using IAM tools to apply the appropriate permissions. AWS strives to make it simple for customers to back up and restore their data. We recommend that you compare the risk and costs associated with losing data to the available solutions to make the best decision for your data and business use cases.

Why do you need backups?

The National Institute of Technology (NIST) Computer Security Incident Handling Guide SP 800-61 Rev. 2 defines a computer security incident as “a violation or imminent threat of violation of computer security policies, acceptable use policies, or standard security practices.” AWS recently updated the AWS Security Incident Response Guide as a resource to help customers throughout the incident response life cycle.

Backup and restore processes help you restore data to a point in time before unauthorized actions. Unauthorized actions can be accidental or part of a security event. Implementing backup and restore processes can help you reduce costs by limiting the number of resources that need backups, associated storage, and overall timelines associated with acceptable Recovery Time Objectives (RTOs) and Recovery Point Objectives (RPOs). For additional guidance on backup solutions and programs, see Top 10 security best practices for securing backups in AWS

How does AWS help?

AWS provides several solutions for backups to integrate with your operational and security incident recovery procedures which I describe in more detail in this section. For additional information, see AWS Backup & Restore.

Amazon EC2

Amazon EC2 provides scalable computing capacity in the AWS Cloud. Using Amazon EC2 can help eliminate your need to invest in hardware up front, helping you to develop and deploy applications faster.

• EBS volumes are the primary persistent storage option for Amazon EC2. Use this block storage for structured data, such as databases, or unstructured data, such as files in a file system on a volume. An EBS snapshot takes a copy of the EBS volume and places it in Amazon S3, where it is stored redundantly in multiple Availability Zones.
• Restore an entire EC2 instance including its associated volumes by restoring an Amazon Machine Image (AMI) backup of your instance. Create AMIs for known good configurations, and integrate them with auto scaling groups to support the scaling and resiliency of your services. For more information on snapshots and AMIs, see Backup and recovery for Amazon EC2 with EBS volumes.
• Create a golden image by preloading needed software and configuration on an EC2 instance, and then creating an image of that. Then, use the resulting image to launch new instances, with updates needed only for the period after image creation.
• Amazon FSx for Windows File Server provides fully-managed Microsoft Windows file servers, backed by a fully native Windows file system. To help ensure file system consistency, Amazon FSx uses the Volume Shadow Copy Service (VSS) in Microsoft Windows. Each FSx for Windows File Server backup contains the information that is needed to create a new file system from the backup, effectively restoring a point-in-time snapshot of the file system. For more information, see Amazon FSx: Working with backups.
• Amazon EC2 Recycle Bin is a data recovery feature that enables you to restore Amazon EBS snapshots and EBS-backed AMIs that were accidentally deleted. If your resources are deleted, they are retained in the Recycle Bin for a period that you specify, before they are permanently deleted.

Transactional databases

In cloud computing, the ideal scenario is to keep persistent transactional states in databases so that those resources are the only things that actively require backups. When used in conjunction with AWS compute services, this minimizes the volume of data that you need to back up. Everything else is restored from a golden image or equivalent through auto scaling or a continuous integration and continuous delivery (CI/CD) pipeline. To estimate costs associated with service usage and the use of backup storage, use the AWS Pricing Calculator. Work backwards from your critical data that requires backups to help limit costs associated with your overall backup solution.

• Amazon Aurora backups are continuous and incremental so that you can quickly restore to any point within the backup retention period. You can specify a backup retention period of 1 to 35 days when you create or modify a database cluster. Aurora backups are stored in Amazon S3.
• Amazon DynamoDB allows you to back up your table data continuously by using point-in-time recovery (PITR). When you use PITR, DynamoDB backs up your table data automatically with per-second granularity to restore to any second in the preceding 35 days. For more information, see DynamoDB PITR.
• Amazon Neptune is a fast, reliable, fully managed graph database service. The core of Neptune is a purpose-built, high-performance graph database engine. Neptune backups are continuous and incremental so that you can quickly restore to any point within the backup retention period. You can specify a backup retention period, from 1 to 35 days, when you create or modify a DB cluster.
• Amazon Relational Database Service (Amazon RDS) creates and saves automated backups of your DB instance during the backup window of your DB instance. Amazon RDS creates a storage volume snapshot of your DB instance, backing up the entire DB instance and not just individual databases. Amazon RDS saves the automated backups of your DB instance according to the backup retention period that you specify between 0 and 35 days. If necessary, you can recover your database to any point in time during the backup retention period.

Amazon Elastic File System

Amazon Elastic File System (Amazon EFS) provides serverless, fully elastic file storage to help you share file data without provisioning or managing storage capacity and performance. The service manages the file storage infrastructure for you to avoid the complexity of deploying, patching, and maintaining complex file system configurations.

The EFS-to-EFS Backup solution is suitable for Amazon EFS file systems in each AWS Region. It includes an AWS CloudFormation template that launches, configures, and runs the AWS services required to deploy the solution. This solution follows AWS best practices for security and availability.

Amazon S3

Amazon S3 is an object storage service that offers industry-leading scalability, data availability, security, and performance designed for 99.999999999% (11 9’s) of durability. When using Amazon S3, you should configure the security of the S3 buckets and objects that are part of your backup solution. For more information on security best practices for Amazon S3, see Top 10 security best practices for securing data in Amazon S3 and The anatomy of ransomware event targeting data residing in Amazon S3.

AWS Backup: A comprehensive solution

If you need a backup strategy for multiple services or to manage backups from a single solution, consider using AWS Backup. AWS Backup is a fully-managed service that makes it simple to centralize and automate data protection across AWS services in the cloud, and on premises. For a list of supported services and resource feature availability, see the AWS Backup Developer Guide.

AWS Backup provides for centralized, policy-based data protection. Your backup data is encrypted using encryption keys managed by AWS Key Management Service (KMS), reducing your need to build and maintain a key management infrastructure. With AWS Backup, you can do the following:

• Set backup retention policies that automatically retain and expire backups, minimizing backup storage costs.
• Copy backups across different AWS Regions and accounts from a central console to help you meet your compliance and disaster recovery needs.
• Create data protection policies and use AWS Organizations to enforce the protection policies throughout the accounts in that organization.
• Set resource-based access policies on backup vaults. Use resource-based access policies to control access to backups in a backup vault across users, rather than having to define permissions for each user.

AWS Backup can help you align with your data protection needs with real-time analytics and insights, as follows:

• You can audit and report on the compliance of your data protection policies to help meet your business and regulatory needs with AWS Backup Audit Manager.
• AWS Backup supports legal hold, which is used when an organization must retain certain data either for preservation, auditing, or as evidence in legal proceedings and e-Discovery.
• You can choose your controls. For information on the available controls, their customizable parameters, and their AWS Config recording resource types, see Choosing your controls. Every control requires the recording resource type AWS Config: resource compliance because this type records your compliance status with either the AWS Backup Framework or a custom framework that you define.

How much will this cost?

To estimate costs for individual services and features, use the AWS Pricing Calculator. For additional cost information, see the feature page for each service at AWS Cloud Products.

Conclusion

In this blog post, you learned about several AWS services and features to help you back up and restore your data. By analyzing and configuring backup and restore capabilities, you can enable resilience from an accidental deletion or security event.