SIEM Solutions for CMMC Compliance

Security Information and Event Management (SIEM) tools are essential for meeting CMMC Level 2 audit and accountability requirements. These tools collect logs from across your environment, correlate events, and alert you to potential security incidents.

SIEM stands for Security Information and Event Management—software that aggregates and analyzes security logs from multiple sources to identify threats and support compliance.

Without a SIEM or equivalent logging solution, meeting CMMC’s audit requirements through manual processes is impractical for most organizations.

Why SIEM Matters for CMMC

CMMC Level 2 includes nine Audit and Accountability requirements that SIEM tools directly address:

Log Creation and Retention (AU.L2-3.3.1)

You must create and retain audit logs to enable monitoring, analysis, and investigation of unauthorized activity. SIEM tools automate log collection from all your systems into a central repository.

User Accountability (AU.L2-3.3.2)

Actions must be traceable to individual users. SIEM correlates user identity across log sources, ensuring you can determine who performed specific actions.

Event Review (AU.L2-3.3.3)

You must review logged events periodically. SIEM dashboards and reports make reviewing thousands of events practical, highlighting what matters.

Audit Failure Alerting (AU.L2-3.3.4)

You must alert when audit logging fails. SIEM tools monitor log sources and alert when systems stop sending logs.

Audit Analysis and Correlation (AU.L2-3.3.5)

You must correlate audit records for investigation. SIEM’s core function is correlating events across sources to identify patterns indicating attacks or policy violations.

Audit Reduction and Reporting (AU.L2-3.3.6)

You must be able to filter and report on audit data. SIEM provides search, filtering, and reporting capabilities to find relevant information quickly.

Audit Protection (AU.L2-3.3.8)

Audit information must be protected from unauthorized access and modification. Centralized SIEM storage protects logs from tampering on source systems.

What to Log for CMMC

Your SIEM should collect logs from all systems in your CUI environment:

CUI stands for Controlled Unclassified Information—sensitive government data requiring protection.

Authentication Events

• Successful and failed logins
• Account lockouts
• Password changes
• MFA events
• Session creation and termination

Authorization Events

• Access to sensitive files and folders
• Permission changes
• Privilege escalation
• Access denials

System Events

• System startup and shutdown
• Service status changes
• Security software events
• Configuration changes

Network Events

• Firewall allows and denies
• VPN connections
• Network traffic anomalies
• External connection attempts

Administrative Actions

• User account changes
• Group membership modifications
• Policy changes
• Software installation

SIEM Options by Organization Size

Enterprise SIEM (Large Organizations)

Full-featured platforms for organizations with dedicated security teams:

Splunk Enterprise Security

• Industry-leading search and analytics
• Extensive integration ecosystem
• High cost, significant expertise required
• Best for organizations with 500+ employees

IBM QRadar

• Strong threat detection capabilities
• Built-in compliance reporting
• Complex deployment and management
• Suitable for large enterprises

Microsoft Sentinel

• Cloud-native SIEM built on Azure
• Strong Microsoft ecosystem integration
• Pay-per-use pricing model
• Good for Microsoft-centric organizations

Mid-Market SIEM (Medium Organizations)

Balanced capability and complexity for growing organizations:

LogRhythm

• User-friendly interface
• Built-in compliance modules
• On-premises and cloud options
• Suitable for 100-500 employees

Securonix

• Cloud-native architecture
• Advanced analytics
• Good compliance reporting
• Mid-market pricing

Exabeam

• User behavior analytics focus
• Automated investigation
• Cloud and on-premises deployment
• Strong for insider threat detection

Small Business SIEM (Small Organizations)

Simplified solutions designed for limited IT resources:

Blumira

• Designed for small and mid-size businesses
• Automated threat detection and response
• Simple deployment and management
• Affordable pricing starting around $1,000/month

Arctic Wolf

• Managed detection and response included
• Security operations center support
• Simplified for resource-constrained teams
• Bundled service model

Huntress

• Originally endpoint-focused, expanding to SIEM
• Managed by Huntress security team
• Very small business-friendly
• Good for MSP-supported clients

Managed SIEM Services

Many small defense contractors lack the staff to operate SIEM tools. Managed SIEM services provide an alternative:

What Managed SIEM Includes:

• SIEM platform deployed and configured
• Log collection from your systems
• 24/7 monitoring by security analysts
• Alert triage and escalation
• Monthly reporting
• Compliance support

Benefits for Small Businesses:

• No need to hire security analysts
• Platform management is handled by the provider
• Expertise included in service fee
• Predictable monthly costs
• Faster deployment than self-managed

Managed SIEM Providers:

• Arctic Wolf
• Expel
• Red Canary
• Alert Logic
• Many regional MSSPs

MSSP stands for Managed Security Service Provider—companies providing outsourced security monitoring and management.

Cost Comparison:

Approach	Monthly Cost	Staff Required
Enterprise SIEM (self-managed)	$5,000 – $20,000+	1-3 FTEs
Mid-market SIEM (self-managed)	$2,000 – $8,000	0.5-1 FTE
Small business SIEM	$1,000 – $3,000	Part-time attention
Managed SIEM service	$2,000 – $6,000	Minimal

FTE stands for Full-Time Equivalent—the workload of one full-time employee.

Implementing SIEM for CMMC

Step 1: Define Your Scope

Identify all systems that must send logs to your SIEM:

• Servers and workstations in a CUI environment
• Network devices (firewalls, routers, switches)
• Security tools (antivirus, EDR, vulnerability scanners)
• Cloud services (Microsoft 365, cloud applications)
• Physical access systems (if integrated)

Step 2: Select Your Solution

Choose a SIEM appropriate for your organization:

• Consider your team’s technical capability
• Evaluate the total cost of ownership
• Assess integration with your existing tools
• Determine if managed services make sense

Step 3: Deploy and Configure

Set up log collection from all source systems:

• Install agents or configure log forwarding
• Ensure all required event types are captured
• Verify logs are flowing correctly
• Configure retention to meet requirements

Step 4: Tune Detection Rules

Customize alerting for your environment:

• Enable relevant detection rules
• Tune thresholds to reduce false positives
• Create custom rules for your specific needs
• Test alerting to ensure it works

Step 5: Establish Processes

Create procedures for ongoing operation:

• Daily log review process
• Alert response procedures
• Escalation procedures for incidents
• Regular reporting schedule

Step 6: Document for CMMC

Maintain documentation that assessors will request:

• System Security Plan sections covering audit controls
• Log retention policy
• Log review procedures
• Evidence of regular reviews

Log Retention Requirements

CMMC does not specify exact retention periods, but considers:

DoD Contract Requirements

Many contracts require retaining logs for specific periods. Common requirements:

• Minimum 90 days online (searchable)
• One year archived retention
• Some contracts require longer retention

Investigation Needs

Longer retention supports incident investigation:

• Advanced attacks may not be detected for months
• Historical logs help understand the attack scope
• Legal proceedings may require an extended history

Practical Recommendation

Retain logs for at least one year, with 90 days readily searchable. Check specific contract requirements for longer periods.

Common SIEM Implementation Mistakes

Mistake 1: Incomplete Log Collection

Failing to collect logs from all systems in scope leaves gaps. Inventory all systems and verify log collection from each.

Mistake 2: Alert Fatigue

Too many alerts overwhelm staff, causing important alerts to be missed. Tune detection rules to reduce noise.

Mistake 3: No Review Process

Deploying SIEM without establishing review processes wastes the investment. Create and follow regular review procedures.

Mistake 4: Insufficient Retention

Deleting logs too quickly prevents investigation of incidents discovered later. Configure adequate retention from the start.

Mistake 5: Over-Engineering

Selecting enterprise SIEM when simpler solutions would suffice wastes budget and creates a management burden. Match the solution to your organization.

Key Takeaways

SIEM tools are essential for meeting CMMC Level 2 audit and accountability requirements. They collect logs from across your environment, enable event correlation, and support the review processes CMMC requires.

Choose a SIEM appropriate for your organization’s size and technical capability. Small businesses should consider managed SIEM services to access enterprise-grade monitoring without dedicated security staff.

Implement SIEM early in your compliance journey—log retention requirements mean you need historical data, not just current monitoring.

Related Articles:

• What is CMMC Level 2?
• CMMC Audit and Accountability Requirements
• Essential Tools for CMMC Compliance
• NIST SP 800-171 Rev 2 – Audit and Accountability
• 32 CFR Part 170 – CMMC Program Rule

Official Sources: This article is based on NIST SP 800-171 Revision 2 Audit and Accountability requirements (Section 3.3) and 32 CFR Part 170. Product information should be verified with vendors.

Need help implementing SIEM for CMMC compliance? Contact Greypike for expert guidance on Level 1 and Level 2 certification, or get started with Obolix to streamline your compliance journey.