AWS Security Blog
Implementing a compliance and reporting strategy for NIST SP 800-53 Rev. 5
Amazon Web Services (AWS) provides tools that simplify automation and monitoring for compliance with security standards, such as the NIST SP 800-53 Rev. 5 Operational Best Practices. Organizations can set preventative and proactive controls to help ensure that noncompliant resources aren’t deployed. Detective and responsive controls notify stakeholders of misconfigurations immediately and automate fixes, thus minimizing the time to resolution (TTR).
By layering the solutions outlined in this blog post, you can increase the probability that your deployments stay continuously compliant with the National Institute of Standards and Technology (NIST) SP 800-53 security standard, and you can simplify reporting on that compliance. In this post, we walk you through the following tools to get started on your continuous compliance journey:
Detective
Preventative
Proactive
Responsive
Reporting
Note on implementation
This post covers quite a few solutions, and these solutions operate in different parts of the security pillar of the AWS Well-Architected Framework. It might take some iterations to get your desired results, but we encourage you to start small, find your focus areas, and implement layered iterative changes to address them.
For example, if your organization has experienced events involving public Amazon Simple Storage Service (Amazon S3) buckets that can lead to data exposure, focus your efforts across the different control types to address that issue first. Then move on to other areas. Those steps might look similar to the following:
- Use Security Hub and Prowler to find your public buckets and monitor patterns over a predetermined time period to discover trends and perhaps an organizational root cause.
- Apply IAM policies and SCPs to specific organizational units (OUs) and principals to help prevent the creation of public buckets and the changing of AWS account-level controls.
- Set up Automated Security Response (ASR) on AWS and then test and implement the automatic remediation feature for only S3 findings.
- Remove direct human access to production accounts and OUs. Require infrastructure as code (IaC) to pass through a pipeline where CloudFormation Guard scans IaC for misconfigurations before deployment into production environments.
Detective controls
Implement your detective controls first. Use them to identify misconfigurations and your priority areas to address. Detective controls are security controls that are designed to detect, log, and alert after an event has occurred. Detective controls are a foundational part of governance frameworks. These guardrails are a second line of defense, notifying you of security issues that bypassed the preventative controls.
Security Hub NIST SP 800-53 security standard
Security Hub consumes, aggregates, and analyzes security findings from various supported AWS and third-party products. It functions as a dashboard for security and compliance in your AWS environment. Security Hub also generates its own findings by running automated and continuous security checks against rules. The rules are represented by security controls. The controls might, in turn, be enabled in one or more security standards. The controls help you determine whether the requirements in a standard are being met. Security Hub provides controls that support specific NIST SP 800-53 requirements. Unlike other frameworks, NIST SP 800-53 isn’t prescriptive about how its requirements should be evaluated. Instead, the framework provides guidelines, and the Security Hub NIST SP 800-53 controls represent the service’s understanding of them.
Using this step-by-step guide, enable Security Hub for your organization in AWS Organizations. Configure the NIST SP 800-53 security standard for all accounts, in all AWS Regions that are required to be monitored for compliance, in your organization by using the new centralized configuration feature; or if your organization uses AWS GovCloud (US), by using this multi-account script. Use the findings from the NIST SP 800-53 security standard in your delegated administrator account to monitor NIST SP 800-53 compliance across your entire organization, or a list of specific accounts.
Figure 1 shows the Security Standard console page, where users of the Security Hub Security Standard feature can see an overview of their security score against a selected security standard.
Figure 1: Security Hub security standard console
On this console page, you can select each control that is checked by a Security Hub Security Standard, such as the NIST 800-53 Rev. 5 standard, to find detailed information about the check and which NIST controls it maps to, as shown in Figure 2.
Figure 2: Security standard check detail
After you enable Security Hub with the NIST SP 800-53 security standard, you can link responsive controls such as the Automated Security Response (ASR), which is covered later in this blog post, to Amazon EventBridge rules to listen for Security Hub findings as they come in.
Prowler
Prowler is an open source security tool that you can use to perform assessments against AWS Cloud security recommendations, along with audits, incident response, continuous monitoring, hardening, and forensics readiness. The tool is a Python script that you can run anywhere that an up-to-date Python installation is located—this could be a workstation, an Amazon Elastic Compute Cloud (Amazon EC2) instance, AWS Fargate or another container, AWS CodeBuild, AWS CloudShell, AWS Cloud9, or another compute option.
Figure 3 shows Prowler being used to perform a scan.
Figure 3: Prowler CLI in action
Prowler works well as a complement to the Security Hub NIST SP 800-53 Rev. 5 security standard. The tool has a native Security Hub integration and can send its findings to your Security Hub findings dashboard. You can also use Prowler as a standalone compliance scanning tool in partitions where Security Hub or the security standards aren’t yet available.
At the time of writing, Prowler has over 300 checks across 64 AWS services.
In addition to integrations with Security Hub and computer-based outputs, Prowler can produce fully interactive HTML reports that you can use to sort, filter, and dive deeper into findings. You can then share these compliance status reports with compliance personnel. Some organizations run automatically recurring Prowler reports and use Amazon Simple Notification Service (Amazon SNS) to email the results directly to their compliance personnel.
Get started with Prowler by reviewing the Prowler Open Source documentation that contains tutorials for specific providers and commands that you can copy and paste.
Preventative controls
Preventative controls are security controls that are designed to prevent an event from occurring in the first place. These guardrails are a first line of defense to help prevent unauthorized access or unwanted changes to your network. Service control policies (SCPs) and IAM controls are the best way to help prevent principals in your AWS environment (whether they are human or nonhuman) from creating noncompliant or misconfigured resources.
IAM
In the ideal environment, principals (both human and nonhuman) have the least amount of privilege that they need to reach operational objectives. Ideally, humans would at the most only have read-only access to production environments. AWS resources would be created through IaC that runs through a DevSecOps pipeline where policy-as-code checks review resources for compliance against your policies before deployment. DevSecOps pipeline roles should have IAM policies that prevent the deployment of resources that don’t conform to your organization’s compliance strategy. Use IAM conditions wherever possible to help ensure that only requests that match specific, predefined parameters are allowed.
The following policy is a simple example of a Deny policy that uses Amazon Relational Database Service (Amazon RDS) condition keys to help prevent the creation of unencrypted RDS instances and clusters. Most AWS services support condition keys that allow for evaluating the presence of specific service settings. Use these condition keys to help ensure that key security features, such as encryption, are set during a resource creation call.
Service control policies
You can use an SCP to specify the maximum permissions for member accounts in your organization. You can restrict which AWS services, resources, and individual API actions the users and roles in each member account can access. You can also define conditions for when to restrict access to AWS services, resources, and API actions. If you haven’t used SCPs before and want to learn more, see How to use service control policies to set permission guardrails across accounts in your AWS Organization.
Use SCPs to help prevent common misconfigurations mapped to NIST SP 800-53 controls, such as the following:
- Prevent governed accounts from leaving the organization or turning off security monitoring services.
- Build protections and contextual access controls around privileged principals.
- Mitigate the risk of data mishandling by enforcing data perimeters and requiring encryption on data at rest.
Although SCPs aren’t the optimal choice for preventing every misconfiguration, they can help prevent many of them. As a feature of AWS Organizations, SCPs provide inheritable controls to member accounts of the OUs that they are applied to. For deployments in Regions where AWS Organizations isn’t available, you can use IAM policies and permissions boundaries to achieve preventative functionality that is similar to what SCPs provide.
The following is an example of policy mapping statements to NIST controls or control families. Note the placeholder values, which you will need to replace with your own information before use. Note that the SIDs map to Security Hub NIST 800-53 Security Standard control numbers or NIST control families.
For a collection of SCP examples that are ready for your testing, modification, and adoption, see the service-control-policy-examples GitHub repository, which includes examples of Region and service restrictions.
For a deeper dive on SCP best practices, see Achieving operational excellence with design considerations for AWS Organizations SCPs.
You should thoroughly test SCPs against development OUs and accounts before you deploy them against production OUs and accounts.
Proactive controls
Proactive controls are security controls that are designed to prevent the creation of noncompliant resources. These controls can reduce the number of security events that responsive and detective controls handle. These controls help ensure that deployed resources are compliant before they are deployed; therefore, there is no detection event that requires response or remediation.
CloudFormation Guard
CloudFormation Guard (cfn-guard) is an open source, general-purpose, policy-as-code evaluation tool. Use cfn-guard to scan Information as Code (IaC) against a collection of policies, defined as JSON, before deployment of resources into an environment.
Cfn-guard can scan CloudFormation templates, Terraform plans, Kubernetes configurations, and AWS Cloud Development Kit (AWS CDK) output. Cfn-guard is fully extensible, so your teams can choose the rules that they want to enforce, and even write their own declarative rules in a YAML-based format. Ideally, the resources deployed into a production environment on AWS flow through a DevSecOps pipeline. Use cfn_guard in your pipeline to define what is and is not acceptable for deployment, and help prevent misconfigured resources from deploying. Developers can also use cfn_guard on their local command line, or as a pre-commit hook to move the feedback timeline even further “left” in the development cycle.
Use policy as code to help prevent the deployment of noncompliant resources. When you implement policy as code in the DevOps cycle, you can help shorten the development and feedback cycle and reduce the burden on security teams. The CloudFormation team maintains a GitHub repo of cfn-guard rules and mappings, ready for rapid testing and adoption by your teams.
Figure 4 shows how you can use Guard with the NIST 800-53 cfn_guard Rule Mapping to scan infrastructure as code against NIST 800-53 mapped rules.
Figure 4: CloudFormation Guard scan results
You should implement policy as code as pre-commit checks so that developers get prompt feedback, and in DevSecOps pipelines to help prevent deployment of noncompliant resources. These checks typically run as Bash scripts in a continuous integration and continuous delivery (CI/CD) pipeline such as AWS CodeBuild or GitLab CI. To learn more, see Integrating AWS CloudFormation Guard into CI/CD pipelines.
To get started, see the CloudFormation Guard User Guide. You can also view the GitHub repos for CloudFormation Guard and the AWS Guard Rules Registry.
Many other third-party policy-as-code tools are available and include NIST SP 800-53 compliance policies. If cfn-guard doesn’t meet your needs, or if you are looking for a more native integration with the AWS CDK, for example, see the NIST-800-53 rev 5 rules pack in cdk-nag.
Responsive controls
Responsive controls are designed to drive remediation of adverse events or deviations from your security baseline. Examples of technical responsive controls include setting more stringent security group rules after a security group is created, setting a public access block on a bucket automatically if it’s removed, patching a system, quarantining a resource exhibiting anomalous behavior, shutting down a process, or rebooting a system.
Automated Security Response on AWS
The Automated Security Response on AWS (ASR) is an add-on that works with Security Hub and provides predefined response and remediation actions based on industry compliance standards and current recommendations for security threats. This AWS solution creates playbooks so you can choose what you want to deploy in your Security Hub administrator account (which is typically your Security Tooling account, in our recommended multi-account architecture). Each playbook contains the necessary actions to start the remediation workflow within the account holding the affected resource. Using ASR, you can resolve common security findings and improve your security posture on AWS. Rather than having to review findings and search for noncompliant resources across many accounts, security teams can view and mitigate findings from the Security Hub console of the delegated administrator.
The architecture diagram in Figure 5 shows the different portions of the solution, deployed into both the Administrator account and member accounts.
Figure 5: ASR architecture diagram
The high-level process flow for the solution components deployed with the AWS CloudFormation template is as follows:
- Detect – AWS Security Hub provides customers with a comprehensive view of their AWS security state. This service helps them to measure their environment against security industry standards and best practices. It works by collecting events and data from other AWS services, such as AWS Config, Amazon GuardDuty, and AWS Firewall Manager. These events and data are analyzed against security standards, such as the CIS AWS Foundations Benchmark. Exceptions are asserted as findings in the Security Hub console. New findings are sent as Amazon EventBridge events.
- Initiate – You can initiate events against findings by using custom actions, which result in Amazon EventBridge events. Security Hub Custom Actions and EventBridge rules initiate Automated Security Response on AWS playbooks to address findings. One EventBridge rule is deployed to match the custom action event, and one EventBridge event rule is deployed for each supported control (deactivated by default) to match the real-time finding event. Automated remediation can be initiated through the Security Hub Custom Action menu, or, after careful testing in a non-production environment, automated remediations can be activated. This can be activated per remediation—it isn’t necessary to activate automatic initiations on all remediations.
- Orchestrate – Using cross-account IAM roles, Step Functions in the admin account invokes the remediation in the member account that contains the resource that produced the security finding.
- Remediate – An AWS Systems Manager Automation Document in the member account performs the action required to remediate the finding on the target resource, such as disabling AWS Lambda public access.
- Log – The playbook logs the results to an Amazon CloudWatch Logs group, sends a notification to an Amazon SNS topic, and updates the Security Hub finding. An audit trail of actions taken is maintained in the finding notes. On the Security Hub dashboard, the finding workflow status is changed from NEW to either NOTIFIED or RESOLVED. The security finding notes are updated to reflect the remediation that was performed.
The NIST SP 800-53 Playbook contains 52 remediations to help security and compliance teams respond to misconfigured resources. Security teams have a choice between launching these remediations manually, or enabling the associated EventBridge rules to allow the automations to bring resources back into a compliant state until further action can be taken on them. When a resource doesn’t align with the Security Hub NIST SP 800-53 security standard automated checks and the finding appears in Security Hub, you can use ASR to move the resource back into a compliant state. Remediations are available for 17 of the common core services for most AWS workloads.
Figure 6 shows how you can remediate a finding with ASR by selecting the finding in Security Hub and sending it to the created custom action.
Figure 6: ASR Security Hub custom action
Findings generated from the Security Hub NIST SP 800-53 security standard are displayed in the Security Hub findings or security standard dashboards. Security teams can review the findings and choose which ones to send to ASR for remediation. The general architecture of ASR consists of EventBridge rules to listen for the Security Hub custom action, an AWS Step Functions workflow to control the process and implementation, and several AWS Systems Manager documents (SSM documents) and AWS Lambda functions to perform the remediation. This serverless, step-based approach is a non-brittle, low-maintenance way to keep persistent remediation resources in an account, and to pay for their use only as needed. Although you can choose to fork and customize ASR, it’s a fully developed AWS solution that receives regular bug fixes and feature updates.
To get started, see the ASR Implementation Guide, which will walk you through configuration and deployment.
You can also view the code on GitHub at the Automated Security Response on AWS GitHub repo.
Reporting
Several options are available to concisely gather results into digestible reports that compliance professionals can use as artifacts during the Risk Management Framework (RMF) process when seeking an Authorization to Operate (ATO). By automating reporting and delegating least-privilege access to compliance personnel, security teams may be able to reduce time spent reporting compliance status to auditors or oversight personnel.
Let your compliance folks in
Remove some of the burden of reporting from your security engineers, and give compliance teams read-only access to your Security Hub dashboard in your Security Tooling account. Enabling compliance teams with read-only access through AWS IAM Identity Center (or another sign-on solution) simplifies governance while still maintaining the principle of least privilege. By adding compliance personnel to the AWSSecurityAudit managed permission set in IAM Identity Center, or granting this policy to IAM principals, these users gain visibility into operational accounts without the ability to make configuration changes. Compliance teams can self-serve the security posture details and audit trails that they need for reporting purposes.
Meanwhile, administrative teams are freed from regularly gathering and preparing security reports, so they can focus on operating compliant workloads across their organization. The AWSSecurityAudit permission set grants read-only access to security services such as Security Hub, AWS Config, Amazon GuardDuty, and AWS IAM Access Analyzer. This provides compliance teams with wide observability into policies, configuration history, threat detection, and access patterns—without the privilege to impact resources or alter configurations. This ultimately helps to strengthen your overall security posture.
For more information about AWS managed policies, such as the AWSSecurityAudit managed policy, see the AWS managed policies.
To learn more about permission sets in IAM Identity Center, see Permission sets.
AWS Audit Manager
AWS Audit Manager helps you continually audit your AWS usage to simplify how you manage risk and compliance with regulations and industry standards. Audit Manager automates evidence collection so you can more easily assess whether your policies, procedures, and activities—also known as controls—are operating effectively. When it’s time for an audit, Audit Manager helps you manage stakeholder reviews of your controls. This means that you can build audit-ready reports with much less manual effort.
Audit Manager provides prebuilt frameworks that structure and automate assessments for a given compliance standard or regulation, including NIST 800-53 Rev. 5. Frameworks include a prebuilt collection of controls with descriptions and testing procedures. These controls are grouped according to the requirements of the specified compliance standard or regulation. You can also customize frameworks and controls to support internal audits according to your specific requirements.
For more information about using Audit Manager to generate automated compliance reports, see the AWS Audit Manager User Guide.
Security Hub Compliance Analyzer (SHCA)
Security Hub is the premier security information aggregating tool on AWS, offering automated security checks that align with NIST SP 800-53 Rev. 5. This alignment is particularly critical for organizations that use the Security Hub NIST SP 800-53 Rev. 5 framework. Each control within this framework is pivotal for documenting the compliance status of cloud environments, focusing on key aspects such as:
- Related requirements – For example, NIST.800-53.r5 CM-2 and NIST.800-53.r5 CM-2(2)
- Severity – Assessment of potential impact
- Description – Detailed control explanation
- Remediation – Strategies for addressing and mitigating issues
Such comprehensive information is crucial in the accreditation and continuous monitoring of cloud environments.
Enhance compliance and RMF submission with the Security Hub Compliance Analyzer
To further augment the utility of this data for customers seeking to compile artifacts and articulate compliance status, the AWS ProServe team has introduced the Security Hub Compliance Analyzer (SHCA).
SHCA is engineered to streamline the RMF process. It reduces manual effort, delivers extensive reports for informed decision making, and helps assure continuous adherence to NIST SP 800-53 standards. This is achieved through a four-step methodology:
- Active findings collection – Compiles ACTIVE findings from Security Hub that are assessed using NIST SP 800-53 Rev. 5 standards.
- Results transformation – Transforms these findings into formats that are both user-friendly and compatible with RMF tools, facilitating understanding and utilization by customers.
- Data analysis and compliance documentation – Performs an in-depth analysis of these findings to pinpoint compliance and security shortfalls. Produces comprehensive compliance reports, summaries, and narratives that accurately represent the status of compliance for each NIST SP 800-53 Rev. 5 control.
- Findings archival – Assembles and archives the current findings for downloading and review by customers.
The diagram in Figure 7 shows the SHCA steps in action.
Figure 7: SHCA steps
By integrating these steps, SHCA simplifies compliance management and helps enhance the overall security posture of AWS environments, aligning with the rigorous standards set by NIST SP 800-53 Rev. 5.
The following is a list of the artifacts that SHCA provides:
- RMF-ready controls – Controls in full compliance (as per AWS Config) with AWS Operational Recommendations for NIST SP 800-53 Rev. 5, ready for direct import into RMF tools.
- Controls needing attention – Controls not fully compliant with AWS Operational Recommendations for NIST SP 800-53 Rev. 5, indicating areas that require improvement.
- Control compliance summary (CSV) – A detailed summary, in CSV format, of NIST SP 800-53 controls, including their compliance percentages and comprehensive narratives for each control.
- Security Hub NIST 800-53 Analysis Summary – This automated report provides an executive summary of the current compliance posture, tailored for leadership reviews. It emphasizes urgent compliance concerns that require immediate action and guides the creation of a targeted remediation strategy for operational teams.
- Original Security Hub findings – The raw JSON file from Security Hub, captured at the last time that the SHCA state machine ran.
- User-friendly findings summary –A simplified, flattened version of the original findings, formatted for accessibility in common productivity tools.
- Original findings from Security Hub in OCSF – The original findings converted to the Open Cybersecurity Schema Framework (OCSF) format for future applications.
- Original findings from Security Hub in OSCAL – The original findings translated into the Open Security Controls Assessment Language (OSCAL) format for subsequent usage.
As shown in Figure 8, the Security Hub NIST 800-53 Analysis Summary adopts an OpenSCAP-style format akin to Security Technical Implementation Guides (STIGs), which are grounded in the Department of Defense’s (DoD) policy and security protocols.
Figure 8: SHCA Summary Report
You can also view the code on GitHub at Security Hub Compliance Analyzer.
Conclusion
Organizations can use AWS security and compliance services to help maintain compliance with the NIST SP 800-53 standard. By implementing preventative IAM and SCP policies, organizations can restrict users from creating noncompliant resources. Detective controls such as Security Hub and Prowler can help identify misconfigurations, while proactive tools such as CloudFormation Guard can scan IaC to help prevent deployment of noncompliant resources. Finally, the Automated Security Response on AWS can automatically remediate findings to help resolve issues quickly. With this layered security approach across the organization, companies can verify that AWS deployments align to the NIST framework, simplify compliance reporting, and enable security teams to focus on critical issues. Get started on your continuous compliance journey today. Using AWS solutions, you can align deployments with the NIST 800-53 standard. Implement the tips in this post to help maintain continuous compliance.
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