AWS Security Blog

Category: Storage

Securing your Amazon S3 buckets: Identifying and remediating over-permissioned access

Misconfigured Amazon Simple Storage Service (Amazon S3) buckets can expose your data to unauthorized access. Without proactive review, S3 bucket policies or Access Control Lists (ACLs) configured with broad access may go unnoticed in your environment. In this post, you learn how to identify and fix over-permissioned S3 buckets across your AWS environment, along with […]

A framework for securely collecting forensic artifacts into S3 buckets

When customers experience a security incident, they need to acquire forensic artifacts to identify root cause, extract indicators of compromise (IoCs), and validate remediation efforts. NIST 800-86, Guide to Integrating Forensic Techniques into Incident Response, defines digital forensics as a process comprised of four basic phases: collection, examination, analysis, and reporting. This blog post focuses […]

How to update CRLs without public access using AWS Private CA

Certificates and the hierarchy of trust they create are the backbone of a secure infrastructure. AWS Private Certificate Authority is a highly available certificate authority (CA) that you can use to create private CA hierarchies, secure your applications and devices with private certificates, and manage certificate lifecycles. A certificate revocation list (CRL) is a file […]

Secure file sharing solutions in AWS: A security and cost analysis guide: Part 2

As introduced in Part 1 of this series, implementing secure file sharing solutions in AWS requires a comprehensive understanding of your organization’s needs and constraints. Before selecting a specific solution, organizations must evaluate five fundamental areas: access patterns and scale, technical requirements, security and compliance, operational requirements, and business constraints. These areas cover everything from […]

Secure file sharing solutions in AWS: A security and cost analysis guide, Part 1

Securely share sensitive data with time-limited, nonce-enhanced presigned URLs that prevent replay attacks, minimizing exposure risks through granular access controls and rigorous monitoring.

How to use AWS Transfer Family and GuardDuty for malware protection

Organizations often need to securely share files with external parties over the internet. Allowing public access to a file transfer server exposes the organization to potential threats, such as malware-infected files uploaded by threat actors or inadvertently by genuine users. To mitigate this risk, companies can take steps to help make sure that files received […]

How to restrict Amazon S3 bucket access to a specific IAM role

February 14, 2025: This post was updated with the recommendation to restrict S3 bucket access to an IAM role by using the aws:PrincipalArn condition key instead of the aws:userid condition key. April 2, 2021: In the section “Granting cross-account bucket access to a specific IAM role,” we updated the second policy to fix an error. […]

Writing IAM Policies: Grant Access to User-Specific Folders in an Amazon S3 Bucket

Mar 25, 2024: We have fixed the JSON code examples which caused errors by replacing the curly quotes with straight quotes. November 14, 2023: We’ve updated this post to use IAM Identity Center and follow updated IAM best practices. In this post, we discuss the concept of folders in Amazon Simple Storage Service (Amazon S3) […]

IAM Policies and Bucket Policies and ACLs! Oh, My! (Controlling Access to S3 Resources)

September 11, 2023: This post has been updated. Updated on July 6, 2023: This post has been updated to reflect the current guidance around the usage of S3 ACL and to include S3 Access Points and the Block Public Access for accounts and S3 buckets. Updated on April 27, 2023: Amazon S3 now automatically enables […]