Vulnerability and Patch Management

Vulnerability and patch management form the cornerstone of proactive security in cardholder data environments, enabling organizations to identify, prioritize, and remediate security findings before they can be exploited. PCI DSS Requirements 5 (Malware Protection), 6 (Secure System and Software Development) and 11 (Security Testing and Monitoring) establish comprehensive requirements for continuous vulnerability assessment, timely patch deployment, and protection against malware that exploits unpatched vulnerabilities. Without effective vulnerability and patch management, organizations accumulate technical debt in the form of known security weaknesses, creating an expanding vulnerable surface that increases the likelihood and potential impact of security incidents. In cloud environments, native vulnerability assessment services and automated patch management capabilities enable organizations to implement continuous vulnerability management with greater speed, consistency, and coverage than traditional periodic assessment approaches. 

Vulnerability and Patch Management within the AWS SRA

The AWS SRA provides foundational guidance for vulnerability and patch management that directly supports key elements of PCI DSS:

Using Amazon Inspector with continuous scanning enabled provides automated vulnerability assessment that exceeds the minimum quarterly scan frequency required by Requirements 11.3.1 and 11.3.2. Inspector discovers EC2 instances, container images in ECR repositories, and Lambda functions, then continuously scans them for software vulnerabilities using the CVE database maintained by the National Vulnerability Database (NVD). Inspector generates findings with severity ratings based on the Common Vulnerability Scoring System (CVSS) version 3.1, including the CVE identifier, affected software package, installed version, fixed version, CVSS score, and remediation guidance. Inspector findings can be published to AWS Security Hub and Amazon EventBridge, enabling centralized tracking and automated remediation workflows. Inspector supports both network reachability analysis (identifying unintended network exposure) and package vulnerability scanning (identifying vulnerable software packages), addressing Requirements 11.3.1 for internal vulnerability scans and Requirement 11.3.1.2 since these are considered authenticated scans.

AWS Security Hub provides centralized vulnerability management by aggregating findings from Amazon Inspector, AWS Config, Amazon GuardDuty, and third-party security products into a unified view. Security Hub workflow status enables tracking of vulnerability remediation from initial detection through verification of remediation, supporting Requirement 11.3.1.1 for rescanning to verify vulnerabilities are corrected. Security Hub insights provide aggregated views of vulnerability trends, showing vulnerability counts by severity, age, resource type, and account, enabling security teams to identify systemic issues and measure vulnerability management program effectiveness. AWS manages the Security Hub infrastructure and PCI DSS security standard logic, while customers are responsible for enabling Security Hub in all accounts, configuring automated response workflows, tracking vulnerabilities through to resolution, and ensuring remediation timelines align with Requirement 6.3.3.

AWS Config with Config Rules provides continuous monitoring of patch compliance status and security configurations. Config Rules can validate that EC2 instances are compliant with patch baselines defined in Systems Manager, that security groups do not permit unrestricted access on sensitive ports, that S3 buckets have encryption enabled, and that other security configurations align with PCI DSS requirements. The managed Config Rule ec2-managedinstance-patch-compliance-status-check evaluates whether EC2 instances managed by Systems Manager are compliant with patch baselines, generating non-compliant findings when instances have missing patches or overdue patches. Config integrates with Systems Manager to provide detailed patch compliance data including which patches are missing, patch severity, and how long patches have been overdue, supporting Requirements 6.3.3, 6.3.2, and 6.3.1 for prioritizing, installing, and documenting security patches. Config conformance packs enable deployment of collections of Config Rules that validate multiple security configurations simultaneously, providing comprehensive compliance monitoring across accounts. AWS manages the Config service infrastructure and managed Config Rules, while customers are responsible for enabling Config in all accounts containing CDE resources, deploying Config Rules that validate patch compliance and security configurations, and configuring automated remediation for common compliance violations.

AWS Systems Manager State Manager maintains desired state configurations for managed instances; security configurations, and monitoring agents remain properly configured over time. State Manager associations define the desired state (such as "all instances must have the CloudWatch Logs agent installed and running") and the schedule for enforcing that state. State Manager can automatically remediate configuration drift by re-applying configurations when instances deviate from the desired state, supporting Requirement 11.5.2 for maintaining secure configurations. State Manager integrates with Systems Manager documents (SSM documents) to define the actions taken to enforce desired state, including installing software, applying patches, modifying configurations, and validating compliance. State Manager execution history is logged to CloudTrail and CloudWatch Logs, providing audit trails of all configuration enforcement activities. AWS manages the State Manager service infrastructure, while customers are responsible for defining State Manager associations that enforce patch compliance and security configurations, monitoring association execution status, and investigating association failures.

AWS Systems Manager Automation provides runbook-based automation for vulnerability remediation and patch deployment. Automation documents define multi-step workflows that can patch instances, update container images, modify security configurations, and verify remediation success. Automation integrates with Amazon EventBridge to enable event-driven remediation, automatically executing runbooks when vulnerabilities are detected by Inspector or when patch compliance violations are detected by Config. Automation documents can include approval steps for high-risk remediation actions, conditional logic to handle different scenarios, and error handling to ensure graceful failure recovery. Automation execution history is logged to CloudTrail and stored in Systems Manager, providing audit trails of all automated remediation activities, supporting Requirement 6.5.1 for documenting vulnerability remediation and change control. AWS provides pre-built automation documents for common remediation scenarios, while customers are responsible for creating custom automation documents for application-specific remediation, configuring event-driven triggers, and monitoring automation execution success rates.

AWS Systems Manager Patch Manager integrated with patch baselines and maintenance windows enables automated, customer defined risk-based patch deployment across EC2 instances and on-premises servers. Patch Manager supports predefined patch baselines for major operating systems including Amazon Linux, Red Hat Enterprise Linux, Ubuntu, Windows Server, SUSE Linux, and macOS, with patch baselines defining which patches are automatically approved for installation based on severity, classification, and release date. Customers can create custom patch baselines that implement the customer defined risk-based patch prioritization required by Requirement 6.3.1, automatically approving critical patches for installation within 30 days and high-risk patches according to customer risk ranking. Patch Manager integrates with maintenance windows to control when patches are installed, minimizing business disruption while ensuring timely patch deployment. Patch Manager provides detailed compliance reporting showing which instances are compliant with patch baselines, which patches are missing, and how long patches have been overdue, supporting Requirement 6.3.3 for documenting security patch installations. Patch Manager can be configured to automatically reboot instances after patch installation when required, or to defer reboots to scheduled maintenance windows. AWS manages the Patch Manager service infrastructure and patch metadata repositories, while customers are responsible for defining patch baselines aligned with organizational risk rankings, configuring maintenance windows, monitoring patch compliance status, and investigating patch installation failures.

Vulnerability and Patch Management beyond the AWS SRA

Some incremental enhancements may be needed to extend the AWS SRA for alignment with additional PCI DSS requirement elements:

Implement risk-based patch prioritization and automation: Create custom AWS Systems Manager patch baselines that implement organizational risk ranking as required by Requirements 6.3.1 and 6.3.2. Define patch baselines that expedite critical patches (CVSS score 9.0-10.0) for installation within 30 days, high-risk patches (CVSS score 7.0-8.9) according to organizational risk assessment, and medium/low-risk patches on a longer timeline. Configure patch baselines with different approval rules for different system types, such as more aggressive patching for internet-facing systems and more conservative patching for sensitive internal systems. Configure Systems Manager maintenance windows with different schedules for different system criticality levels, such as weekly maintenance windows for development systems and monthly maintenance windows for production systems. Deploy Amazon EventBridge rules that trigger AWS SNS notifications when critical patches are available, enabling security teams to expedite patch deployment for high-risk vulnerabilities, supporting Requirements 6.3.1, 6.3.2, and 6.3.3 for timely, risk-based patch deployment.

Configure automated patch compliance monitoring and reporting: Deploy AWS Config that continuously monitor patch compliance status for all EC2 instances and on-premises servers managed by Systems Manager. Create custom Config Rules using AWS Lambda that evaluate patch compliance against organizational risk rankings, identifying instances with critical patches overdue by more than 30 days, high-risk patches overdue according to risk-based timelines, or instances that have not been scanned for patches in the past 30 days. Configure Amazon EventBridge rules to trigger AWS Lambda functions that generate patch compliance reports on a weekly basis, documenting patch compliance rates by account, application, and system type, overdue patches with severity and age, instances requiring remediation, and patch deployment trends over time. Integrate with Amazon QuickSight to create interactive patch compliance dashboards showing compliance trends, mean time to patch (MTTP) metrics, patch deployment success rates, and comparison of patch compliance across accounts and applications. 

Implement automated vulnerability remediation workflows: Deploy AWS Systems Manager Automation documents that define automated remediation actions for common vulnerability types detected by Amazon Inspector. Create automation documents that respond to Inspector findings by automatically applying security patches using Patch Manager (for operating system and application vulnerabilities), updating container images in ECR to patched versions (for container vulnerabilities), updating Lambda function runtime versions (for serverless vulnerabilities), or modifying security group rules (for unintended network exposure findings). Configure AWS Security Hub custom actions that enable security analysts to trigger automated remediation with a single click from the Security Hub console, with automation documents executing the appropriate remediation based on finding type. Deploy Amazon EventBridge rules that automatically execute remediation workflows for critical vulnerabilities (CVSS score 9.0 or higher) while requiring manual approval for lower-severity findings, balancing automation speed with change control requirements. Configure AWS Step Functions workflows that orchestrate multi-step remediation processes, including creating snapshots before remediation, executing remediation actions, validating remediation success, triggering Inspector rescans to verify vulnerability resolution, and updating Security Hub workflow status, supporting Requirements 11.3.1.3 and 6.3.3 for timely vulnerability remediation and verification.

Implement container image vulnerability management: Configure Amazon ECR with enhanced scanning enabled on all repositories containing images used in the CDE. Deploy Amazon ECR lifecycle policies that automatically delete or quarantine container images with critical vulnerabilities (CVSS score 9.0 or higher) that have been unresolved for more than 30 days, preventing deployment of vulnerable images to production environments. Create AWS Lambda functions that monitor Amazon ECR scan results via Amazon EventBridge, identify base images with vulnerabilities, and automatically trigger AWS CodePipeline pipelines to rebuild container images using patched base images. Configure CodePipeline with security gates that block deployment of container images with critical or high-severity vulnerabilities, requiring manual approval or vulnerability remediation before deployment proceeds. Deploy AWS Lambda functions that generate container image vulnerability reports showing vulnerability counts by repository, image age, base image vulnerabilities versus application dependency vulnerabilities, and remediation timelines, supporting Requirements 6.3.1, 6.3.3, and 11.3.1.1 for identifying and remediating vulnerabilities in containerized applications. Integrate with Amazon ECS and Amazon EKS admission controllers to prevent deployment of container images that have not been scanned or that contain critical vulnerabilities, enforcing vulnerability management policies at deployment time.

Configure vulnerability exception and risk acceptance workflow: Deploy AWS Lambda functions and Amazon DynamoDB to create a vulnerability exception management system that tracks vulnerabilities that cannot be remediated within standard timelines due to technical constraints, business requirements, or vendor limitations. Configure the exception management system to require documented business justification, compensating controls, risk acceptance approval from authorized personnel, and expiration dates for all vulnerability exceptions. Integrate the exception management system with AWS Security Hub to automatically suppress findings for approved exceptions while maintaining audit trails of exception approvals and expirations. Deploy Amazon EventBridge rules that trigger notifications via Amazon SNS when vulnerability exceptions are approaching expiration, requiring re-evaluation of risk acceptance decisions. Create AWS Lambda functions that generate quarterly vulnerability exception reports showing all active exceptions, compensating controls, risk owners, and expiration dates, supporting Requirements 6.3.3 and 11.3.1.1 for documenting vulnerability management decisions and risk acceptance. 

Implement patch testing and validation workflows: Deploy dedicated AWS accounts for patch testing using AWS Organizations, enabling isolated testing of patches before deployment to production environments. Configure AWS Systems Manager to deploy patches to test environments first, with automated testing using AWS Lambda functions that validate application functionality, performance, and security after patch installation. Create AWS Step Functions workflows that orchestrate the complete patch lifecycle, including deploying patches to test environments, executing automated tests, collecting test results, requiring manual approval for production deployment, deploying patches to production environments in phases (such as canary deployments to 10% of instances, then 50%, then 100%), and monitoring application health during production deployment. Deploy Amazon CloudWatch alarms that detect application failures or performance degradation after patch deployment, automatically triggering rollback procedures using AWS Systems Manager to restore instances to pre-patch snapshots. Configure AWS Lambda functions that generate patch deployment reports documenting patches tested, test results, production deployment timelines, and any issues encountered, supporting Requirements 6.3.3 and 6.5.1 for documenting patch installations and change control processes.