Automated Security Response on AWS

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Automated Security Response (ASR) on AWS is a solution that enables AWS Security Hub customers to remediate findings with a single click using sets of predefined response and remediation actions called Playbooks. The remediations are implemented as AWS Systems Manager automation documents. The solution includes remediations for issues such as unused access keys, open security groups, weak account password policies, VPC flow logging configurations, and public S3 buckets. Remediations can also be configured to trigger automatically when findings appear in AWS Security Hub.

The solution includes the playbook remediations for some of the security controls defined as part of the following standards:

• AWS Foundational Security Best Practices (FSBP) v1.0.0
• Center for Internet Security (CIS) AWS Foundations Benchmark v1.2.0
• Center for Internet Security (CIS) AWS Foundations Benchmark v1.4.0
• Payment Card Industry (PCI) Data Security Standard (DSS) v3.2.1
• National Institute of Standards and Technology (NIST) Special Publication 800-53 Revision 5

A Playbook called Security Control is included that allows operation with AWS Security Hub's Consolidated Control Findings feature.

Note: To deploy the solution without building from the source code, use the CloudFormation templates linked from the Solution Landing Page.

Architecture Diagram

Customizing the Solution

Detailed instructions for creating a new automated remediation in an existing Playbook can be found in the Implementation Guide. Instructions for creating an entirely new Playbook are below.

Note: If you choose to continue, please be aware that reading and adjusting the source code will be necessary.

Prerequisites for Customization

• a Linux client with the following software
  • AWS CLI v2
  • Python 3.7+ with pip
  • AWS CDK 1.155.0+
  • Node.js with npm
• source code downloaded from GitHub
• two S3 buckets (minimum): 1 global and 1 for each region where you will deploy
  • An Amazon S3 Bucket for solution templates - accessed globally via https.
  • An Amazon S3 Bucket for source code - regional.

Obtaining Source Code

Building from GitHub source will allow you to modify the solution to suit your specific needs. The process consists of downloading the source from GitHub, creating buckets to be used for deployment, building the solution, and uploading the artifacts needed for deployment.

Clone or download the repository to a local directory on your linux client. Note: if you intend to modify the solution you may wish to create your own fork of the GitHub repo and work from that. This allows you to check in any changes you make to your private copy of the solution.

Git Clone example:

git clone https://github.com/aws-solutions/automated-security-response-on-aws.git

Download Zip example:

wget https://github.com/aws-solutions/automated-security-response-on-aws/archive/main.zip

Custom Playbooks

Go to source/playbooks in the solution source downloaded above. In this folder is a Playbook skeleton, NEWPLAYBOOK. Copy this entire folder and its contents as a new folder under source/playbooks. The naming convention is the security standard abbreviation followed by the version number, as they appear in the StandardsControlArn in the AWS Standard Finding Format for the security control.

Example

For PCI-DSS, we used "PCI" for the standard abbreviation. The version is 321: PCI321

"StandardsControlArn": "arn:aws:securityhub:us-east-1:111111111111:control/pci-dss/v/3.2.1/PCI.IAM.7"

For CIS AWS Foundations Benchmark, we use "CIS". The version is 120: CIS120

"StandardsControlArn": "arn:aws:securityhub:us-east-1:111111111111:control/cis-aws-foundations-benchmark/v/1.2.0/2.4"

Unless noted, all of the following changes are within the folder you just created for your new playbook.

1. Rename the typescript file in bin to match the (lower case) name of your new playbook. Ex. pci321.ts
2. Update cdk.json with the new file name
3. Rename the test typescript in the test subfolder similarly. Ex. pci321_stack.test.ts
4. Update the description.txt, README.md, and support.txt, following the example within.
5. Rename ssmdocs/scripts/newplaybook_parse_input.py as desired. This script parses the finding data. You will likely not need to modify it, as it's fairly robust. See other Playbooks for examples of its use.

Configure the Playbook

Edit bin/<standard>.ts. The following 3 lines are critical to definition of the Playbook. These values enable ASR to map from the StandardsControlArn in a finding to your remediations.

const standardShortName = "NPB";
const standardLongName = "New Playbook";
const standardVersion = "1.1.1"; // DO NOT INCLUDE 'V'

standardShortName can be as you wish. General recommendation is to make it short and meaningful. Ex. PCI, CIS, FSBP. This is the name used in many labels throughout the solution. standardLongName must match the StandardsControlArn, as pci-dss in the above example. standardVersion must match the StandardsControlArn version, as .../v/3.2.1/... in the above example.

Having established these values, your runbooks in /ssmdocs will be named: -.yaml

As you write your SSM runbooks, you will add them to the stack in the following code, where control must match the field from the StandardsControlArn:

const remediations: IControl[] = [{ control: "RDS.6" }];

Add your playbook as a new nested stack in the solution template

Edit playbooks/playbook-index.ts to include the new playbook.

Add the new playbook to the end of the standardPlaybookProps array.

Important Do not change the order of the items in this array. Doing so will change the App Registry logical IDs for the nested stacks. This will cause an error when updating the solution.

Interface:

export interface PlaybookProps {
  name: string; // Playbook short name
  useAppRegistry: boolean; // Add this playbook's nested stack to app registry for the solution
  defaultParameterValue?: 'yes' | 'no'; // Default value for enabling this playbook in CloudFormation. Will default to 'no' if not provided.
  description?: string; // Description for the CloudFormation parameter. Solution will provide a generated description if left blank.
}

Create the Remediations

Remediations are executed using SSM Automation Runbooks. Each control has a specific runbook. ASR Runbooks must follow the naming convention in the /ssmdocs folder:

-.yaml

Follow examples from other Playbooks. Your ASR runbook must parse the finding data, extract the fields needed for remediation, and execute a remediation runbook, passing the role name.

Remediation runbooks are defined in the /source/remediation_runbooks and /source/solution_deploy/remediation_runbooks-stack.ts. The remediation examples provided with the solution are fairly robust and self-documenting. Each definition creates an IAM role and an SSM runbook that is called by the ASR runbook.

Build and Deploy

AWS Solutions use two buckets: a bucket for global access to templates, which is accessed via HTTPS, and regional buckets for access to assets within the region, such as Lambda code. You will need:

• One global bucket that is access via the http end point. AWS CloudFormation templates are stored here. It must end with "-reference. Ex. "mybucket-reference"
• One regional bucket for each region where you plan to deploy using the name of the global bucket as the root, and suffixed with the region name. Ex. "mybucket-us-east-1"
• Your buckets should be encrypted and disallow public access

Note: When creating your buckets, ensure they are not publicly accessible. Use random bucket names. Disable public access. Use KMS encryption. And verify bucket ownership before uploading.

Build the solution

First ensure that you've run npm install in the source folder.

Next from the deployment folder in your cloned repo, run build-s3-dist.sh, passing the root name of your bucket (ex. mybucket) and the version you are building (ex. v1.0.0). We recommend using a semver version based on the version downloaded from GitHub (ex. GitHub: v1.0.0, your build: v1.0.0.mybuild)

chmod +x build-s3-dist.sh
build-s3-dist.sh -b <bucketname> -v <version>

Run Unit Tests

Some Python unit tests execute AWS API calls. The calls that create, read, or modify resources are stubbed, but some calls to APIs that do not require any permissions execute against the real AWS APIs (e.g. STS GetCallerIdentity). The recommended way to run the unit tests is to configure your credentials for a no-access console role.

cd ./deployment
chmod +x ./run-unit-tests.sh
./run-unit-tests.sh

Confirm that all unit tests pass.

Upload to your buckets

Note: Verify bucket ownership before uploading.

By default, the templates created by build-s3-dist.sh expect the software to be stored in automated-security-response-on-aws/v<version>. If in doubt, view the template.

Use a tool such as the AWS S3 CLI "sync" command to upload your templates to the reference bucket and code to the regional bucket.

Deploy

See the Automated Security Response on AWS Implementation Guide for deployment instructions, using the link to the SolutionDeployStack.template from your bucket, rather than the one for AWS Solutions. Ex. https://mybucket-reference.s3.amazonaws.com/automated-security-response-on-aws/v1.3.0.mybuild/aws-sharr-deploy.template

Directory structure

|-.github/                [ GitHub pull request template, issue templates, and workflows ]
|-deployment/             [ Scripts used to build, test, and upload templates for the solution ]
|-simtest/                [ Tool and sample data used to simulate findings for testing ]
|-source/                 [ Solution source code and tests ]
  |-layer/                [ Common functions used by the Orchestrator and custom resource providers ]
  |-lib/                  [ Solution CDK ]
    |-appregistry/        [ Resources for integration with Service Catalog AppRegistry ]
    |-cdk-helper/         [ CDK helper functions ]
    |-member/             [ Member stack helper functions ]
    |-tags/               [ Resource tagging helper functions ]
  |-Orchestrator/         [ Orchestrator Step Function Lambda Functions ]
  |-playbooks/            [ Playbooks ]
    |-AFSBP/              [ AWS FSBP v1.0.0 playbook ]
    |-CIS120/             [ CIS v1.2.0 playbook ]
    |-CIS140/             [ CIS v1.4.0 playbook ]
    |-common/             [ Common scripts used by multiple playbooks ]
    |-NEWPLAYBOOK/        [ Example playbook ]
      |-bin/              [ Playbook CDK App ]
      |-ssmdocs/          [ Control runbooks ]
    |-PCI321/             [ PCI-DSS v3.2.1 playbook ]
    |-SC/                 [ Security Control playbook ]
  |-remediation_runbooks/ [ Shared remediation runbooks ]
    |-scripts/            [ Scripts used by remediation runbooks ]
  |-solution_deploy/      [ Solution CDK App and custom resource providers ]
    |-bin/                [ Solution CDK App ]
    |-source/             [ Custom resource providers ]
  |-test/                 [ CDK and SSM document unit tests ]

Collection of operational metrics

This solution collects anonymized operational metrics to help AWS improve the quality of features of the solution. For more information, including how to disable this capability, please see the Implementation Guide

License

Distributed under the Apache License Version 2.0. For more information, see LICENSE.txt.