S3TK : A Security Toolkit For Amazon S3

S3TK is a security toolkit for Amazon S3.

Installation

Run:

pip install s3tk

You can use the AWS CLI to set up your AWS credentials:

pip install awscli
aws configure

Commands

Scan

Scan your buckets for:

• ACL open to public
• policy open to public
• logging enabled
• versioning enabled
• default encryption enabled

s3tk scan

Only run on specific buckets

s3tk scan my-bucket my-bucket-2

Also works with wildcards

s3tk scan “my-bucket*”

Confirm correct log bucket(s) and prefix

s3tk scan –log-bucket my-s3-logs –log-bucket other-region-logs –log-prefix “{bucket}/”

Skip logging, versioning, or default encryption

s3tk scan –skip-logging –skip-versioning –skip-default-encryption

Get email notifications of failures (via SNS)

s3tk scan –sns-topic arn:aws:sns:…

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List Policy

List bucket policies

s3tk list-policy

Only run on specific buckets

s3tk list-policy my-bucket my-bucket-2

Show named statements

s3tk list-policy –named

Set Policy

Note: This replaces the previous policy

Only private uploads

s3tk set-policy my-bucket –no-object-acl

Delete Policy

Delete policy

s3tk delete-policy my-bucket

Enable Logging

Enable logging on all buckets

s3tk enable-logging –log-bucket my-s3-logs

Only on specific buckets

s3tk enable-logging my-bucket my-bucket-2 –log-bucket my-s3-logs

Set log prefix ({bucket}/ by default)

s3tk enable-logging –log-bucket my-s3-logs –log-prefix “logs/{bucket}/”

Use the --dry-run flag to test

A few notes about logging:

• buckets with logging already enabled are not updated at all
• the log bucket must in the same region as the source bucket – run this command multiple times for different regions
• it can take over an hour for logs to show up

Enable Versioning

Enable versioning on all buckets

s3tk enable-versioning

Only on specific buckets

s3tk enable-versioning my-bucket my-bucket-2

Use the --dry-run flag to test

Enable Default Encryption

Enable default encryption on all buckets

s3tk enable-default-encryption

Only on specific buckets

s3tk enable-default-encryption my-bucket my-bucket-2

This does not encrypt existing objects – use the encrypt command for this

Use the --dry-run flag to test

Scan Object ACL

Scan ACL on all objects in a bucket

s3tk scan-object-acl my-bucket

Only certain objects

s3tk scan-object-acl my-bucket –only “*.pdf”

Except certain objects

s3tk scan-object-acl my-bucket –except “*.jpg”

Reset Object ACL

Reset ACL on all objects in a bucket

s3tk reset-object-acl my-bucket

This makes all objects private. See bucket policies for how to enforce going forward.

Use the --dry-run flag to test

Specify certain objects the same way as scan-object-acl

Encrypt

Encrypt all objects in a bucket with server-side encryption

s3tk encrypt my-bucket

Use S3-managed keys by default. For KMS-managed keys, use:

s3tk encrypt my-bucket –kms-key-id arn:aws:kms:…

For customer-provided keys, use:

s3tk encrypt my-bucket –customer-key secret-key

Use the --dry-run flag to test

Specify certain objects the same way as scan-object-acl

Note: Objects will lose any custom ACL

Delete Unencrypted Versions

Delete all unencrypted versions of objects in a bucket

s3tk delete-unencrypted-versions my-bucket

For safety, this will not delete any current versions of objects

Use the --dry-run flag to test

Specify certain objects the same way as scan-object-acl

Scan DNS

Scan Route 53 for buckets to make sure you own them

s3tk scan-dns

Otherwise, you may be susceptible to subdomain takeover

Credentials

Credentials can be specified in ~/.aws/credentials or with environment variables. See this guide for an explanation of environment variables.

You can specify a profile to use with:

AWS_PROFILE=your-profile s3tk

Upgrading

Run:

pip install s3tk –upgrade

To use master, run:

pip install git+https://github.com/ankane/s3tk.git –upgrade

Docker

Run:

docker run -it ankane/s3tk aws configure

Commit your credentials:

docker commit $(docker ps -l -q) my-s3tk

And run:

docker run -it my-s3tk s3tk scan