Atrás 
Introduction
Best practices for securing an AWS environment have been well-documented and generally accepted, such as AWS’s guidance. However, organizations may still find it challenging on how to begin applying this guidance to their specific environments.
- Which controls should be applied out-of-the-box vs. customized?
- What pitfalls exist in implementing the various controls or checks?
- How do you prioritize remediation of the “sea of red” violations?
In this blog series, we’ll analyze anonymized data from Netskope customers that include security settings of 650,000 entities from 1,143 AWS accounts across several hundred organizations. We’ll look at the configuration from the perspective of the best practices, see what’s commonly occurring in the real world, and:
- Discuss specific risk areas that should be prioritized
- Identify underlying root causes and potential pitfalls
- Focus on practical guidance for applying the Benchmark to your specific environment
This blog post focuses on IAM security controls related to bucket storage. Based on the Netskope dataset analyzed, we will highlight two opportunities to improve security:
- Remove Public Buckets: Review public S3 buckets and set Block Public Access. Over 58% of buckets do not have Block Public Access set.
- Encryption: Encrypt S3 buckets and EBS volumes and enforce HTTPS transfers for S3 bucket access. More than 40% of S3 buckets and EBS volumes are not encrypted at rest, and more than 88% of buckets allow unencrypted access using HTTP.
Storage
Four controls related to storage best practices are:
- Ensure that your Amazon S3 buckets are not publicly accessible
- Enforce encryption of data in transit from S3 buckets
- Set server-side data encryption for S3 buckets
- Set server-side data encryption for EBS volumes
In our dataset, we looked at configuration settings for 26,228 buckets and 132,912 volumes across 1,143 accounts, with the following findings:
| # | Best Practice | # Violations | % |
|---|---|---|---|
| 1 | Ensure that your Amazon S3 buckets are not publicly accessible | 15,293 | 58.3 |
| 2 | Enforce encryption of data in transit from S3 buckets | 23,143 | 88.2 |
| 3 | Set server-side data encryption for S3 buckets | 1,162 | 44.3 |
| 4 | Set server-side data encryption for EBS volumes | 59,877 | 45.0 |
1. Public S3 Buckets
Background: Access to data residing on S3 buckets can be complicated since permissions can be specified in different ways with object ACLs, bucket ACLs, bucket policies, and IAM user policies. In some cases, if a bucket is used to serve public content e.g. for a web server, then public access (to anonymous or any authenticated user) is expected. However, in many cases, publicly accessible data is unintended and is a common cause of data loss.
AWS provides a setting, “Block Public Access”, which when set, ensures that the bucket is private by ignoring any public ACLs or public policies. Further, it prevents changing of bucket/object ACLs and bucket policies to make it public. Conversely, when it is disabled, then any public ACLs and policies will take effect and authorized users are also able to change the bucket ACLs and policies.