Critical Security Process

Systematic Patch
Management

60% of breaches exploit known vulnerabilities with available patches. Implement a robust patch management process to systematically identify, prioritize, and deploy security updates across your infrastructure.

Systematic Process

Automated Scanning

Risk-Based Priority

Why Patch Management Is Critical

Unpatched vulnerabilities are the most common attack vector. Every day you delay patching is a day attackers have to exploit known weaknesses.

60%

OF BREACHES

Exploit known vulnerabilities with available patches

143M

RECORDS STOLEN

Equifax breach caused by a single unpatched Apache Struts vulnerability

200K+

SYSTEMS AFFECTED

WannaCry ransomware exploited an unpatched Windows SMB vulnerability globally

Systems Requiring Patches

Comprehensive patching across all layers of your infrastructure

Operating Systems

OS-level vulnerabilities in Linux, Windows, macOS servers and workstations

Patch Frequency: Monthly + Critical

Examples:

• Kernel vulnerabilities
• System libraries
• Core services
• Drivers

Common Tools:

WSUSapt/yumWindows UpdateAnsible

Applications & Libraries

Third-party software, frameworks, and dependencies used by your applications

Patch Frequency: Weekly + Critical

Examples:

• Web servers (Apache, Nginx)
• Databases (PostgreSQL, MySQL)
• Runtime environments
• npm/pip packages

Common Tools:

DependabotSnykRenovateOWASP Dependency-Check

Containers & Images

Base images, system packages, and dependencies within containerized workloads

Patch Frequency: Continuous

Examples:

• Base images (Alpine, Ubuntu)
• Container runtime
• Orchestration platform
• Registry vulnerabilities

Common Tools:

TrivyGrypeDocker ScoutHarbor

Implementation Roadmap

Build a systematic patch management process from the ground up

Build Complete Asset Inventory

1 week

You cannot patch what you do not know exists. Create a comprehensive inventory of all systems.

Tasks:

Catalog all servers (physical, virtual, cloud instances)
Document all applications and their versions
List all container images in use (including base images)
Track all network devices, IoT devices, and endpoints
Maintain inventory in a CMDB or asset management system
Tag assets by criticality (production, staging, dev) and ownership

Deploy Vulnerability Scanning

3-5 days

Automated scanning identifies vulnerable software and missing patches

Tasks:

Deploy vulnerability scanner (Nessus, Qualys, OpenVAS, or Wiz)
Configure authenticated scans for accurate results (provide scanner with credentials)
Scan OS, applications, and container images
Schedule automated weekly scans + ad-hoc scans after major CVE disclosures
Integrate scanning into CI/CD pipelines for container images
Set up alerts for critical/high severity vulnerabilities

Establish Prioritization Framework

2-3 days

Not all vulnerabilities are equal. Prioritize patching based on risk and exploitability.

Tasks:

Use CVSS scores as baseline (Critical: 9.0-10.0, High: 7.0-8.9, Medium: 4.0-6.9)
Check CISA KEV (Known Exploited Vulnerabilities) catalog for active exploitation
Factor in asset criticality: production > staging > dev
Prioritize internet-facing systems and systems handling sensitive data
Use EPSS (Exploit Prediction Scoring System) to assess likelihood of exploitation
Define SLAs: Critical patches within 48 hours, High within 7 days, Medium within 30 days

Test Patches in Staging

Ongoing

Always test patches before production deployment to avoid breaking changes

Tasks:

Maintain staging environment mirroring production
Deploy patches to staging first
Run automated test suites after patching
Verify application functionality and integrations
Monitor for performance degradation
Document any compatibility issues and workarounds

Automate Patch Deployment

1-2 weeks

Manual patching does not scale. Automate deployment with rollback capabilities.

Tasks:

Use automation tools: Ansible, Puppet, Chef, WSUS, or cloud-native tools (AWS Systems Manager)
Deploy OS patches via configuration management or orchestration tools
Rebuild container images with updated base layers and redeploy
Use GitOps (ArgoCD, FluxCD) to deploy updated container images
Implement canary deployments for gradual rollout
Ensure rollback procedures are tested and documented

Monitor and Verify

Ongoing

Confirm patches are applied successfully and systems remain secure

Tasks:

Re-scan systems after patching to verify vulnerabilities are resolved
Monitor application logs and metrics for post-patch issues
Track patch compliance metrics: % of systems patched within SLA
Generate monthly vulnerability reports for management
Conduct quarterly audits to identify unpatched systems
Continuously improve process based on failures and near-misses

Best Practices by System Type

Operating Systems (Linux/Windows)

Enable automatic security updates for non-production systems
For production: test patches in staging, deploy in maintenance windows
Use configuration management (Ansible, Puppet) for consistent patching
Maintain kernel versioning strategy (LTS kernels for stability)
Always have rollback/snapshot capability before patching

Applications (Web servers, Databases, Runtimes)

Subscribe to security mailing lists for all critical applications
Test application compatibility with updated dependencies
Use blue-green deployments or canary releases for application updates
Monitor vendor security advisories (e.g., PostgreSQL, Nginx, Node.js)
Keep dependencies up to date—outdated libraries are attack vectors

Container Images

Scan images during build (shift-left security)
Use minimal base images (Alpine, Distroless) to reduce attack surface
Rebuild images regularly even if code has not changed (base layer updates)
Implement image signing and verification
Use immutable tags or content-addressable digests, not "latest"
Automate image rebuilds when base images or dependencies are updated

Common Pitfalls to Avoid

Patching too slowly due to fear of breaking production

Solution: Improve staging environment accuracy and test coverage. Use canary deployments. The risk of unpatched vulnerabilities is higher than the risk of a tested patch.

No rollback plan when patches cause issues

Solution: Always create snapshots/backups before patching. Document rollback procedures. Test rollbacks in staging.

Ignoring container image vulnerabilities

Solution: Scan images in CI/CD. Rebuild images regularly even if application code has not changed. Use vulnerability scanning in registries.

No visibility into what systems are running

Solution: Maintain comprehensive asset inventory. Use discovery tools to find shadow IT. Tag all cloud resources.

Treating all vulnerabilities equally

Solution: Prioritize using CVSS, CISA KEV, EPSS, asset criticality, and exploitability. Focus on critical and high severity vulnerabilities in production first.