Garrison Agent - AWS S3

This is a part of the Garrison security project. This agent provides various AWS S3 compliance checks.

Checks Provided

Function Name	Description
check_encryption	Alerts if encryption is not enabled for an S3 bucket.
check_public_access_block	Alerts if there are any buckets defined without a public access block.

Installation & Example

Docker Hub - https://hub.docker.com/r/forward3d/garrison-agent-aws-s3/

docker pull forward3d/garrison-agent-aws-s3
docker run --rm -e "GARRISON_URL=https://garrison.internal.acme.com" forward3d/garrison-agent-aws-s3 check_encryption
docker run --rm -e "GARRISON_URL=https://garrison.internal.acme.com" -e "GARRISON_AWS_REGIONS=eu-west-1,us-west-2" forward3d/garrison-agent-aws-s3 check_public_access

Agent Specific Configuration

These are additional specific configuration options for this agent. Global agent configurations still apply.

Environmental Variable	Default	Expects
GARRISON_AWS_REGIONS	all [1]	Comma Separated Strings eg. eu-west-1,us-west-2

AWS Authentication

As this requires access to the AWS API you will need this IAM policy as a minimum for it to operate correctly.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Action": [
              "s3:GetBucketEncryption",
              "s3:GetBucketPublicAccessBlock",
              "s3:GetBucketLocation",
              "s3:ListAllMyBuckets"
            ],
            "Resource": "*",
            "Effect": "Allow"
        }
    ]
}

We recommend using EC2/ECS Task roles so that you don't need to send credentials into the container, however if you can't use those or want to send in specific Access Keys and Secret keys, please see the AWS Documentation as to how you do that.

Cross-Account Authentication (STS AssumeRole)

If you run Garrison agents in one account, and want to reach into other AWS accounts you need to send in extra environmental variables to support that.

Environmental Variable	Value
AWS_ACCOUNT_ID	Not used as part of authentication, but to override the tag set on any alerts
AWS_ASSUME_ROLE_CREDENTIALS_ARN	Arn of the role (in the other account) you wish to assume

Check Specific Configuration

Some checks provided by this agent have extra configuration options.

check_public_access

Environmental Variable	Default
GARRISON_S3_ALLOWED_PUBLIC_BUCKETS