Small businesses working under FAR 52.204-21 and aiming for CMMC 2.0 Level 1 compliance must implement both periodic vulnerability scans and real-time system integrity checks to identify, prioritize, and remediate risks; this post shows a practical, audit-focused way to build that program tied to the SI.L1-B.1.XV control expectation so you can produce defensible evidence during assessments.
Program design: objectives, scope, and evidence expectations
Start by documenting the program's objectives in a short policy: scope (all assets that store or process CUI or that are in scope per contract), types of scans (authenticated periodic scans, unauthenticated external scans, web app scans, and real-time endpoint/traffic monitoring), frequency, ownership, and the types of evidence you will retain for audits (scan reports, raw logs, remediation tickets, signed exception forms, and configuration snapshots of scanners). For Compliance Framework practice mapping, include the control ID SI.L1-B.1.XV in all artifacts so assessors can trace requirements to evidence.
Periodic scanning: what to run, cadence, and technical details
Implement at least three periodic scan types: quick daily/weekly discovery scans (low-impact, unauthenticated) to detect new hosts, weekly authenticated internal scans (credentialed) for depth, and monthly or quarterly comprehensive external scans (from an external IP) for exposed services. Technical recommendations: use credentialed Nessus/OpenVAS/Qualys scans for internal hosts to identify missing patches and insecure configurations; configure authenticated checks (SSH/Windows SMB with a read-only service account) to detect missing packages or insecure permissions; enable plugin vulnerability families that map to CVE and CVSS. For small businesses with limited budget, run OpenVAS internally and schedule a paid external scan quarterly via a managed provider or cloud-native scanners (AWS Inspector, Azure Defender) for coverage of cloud workloads.
Scan configuration and safe practices
Use credentialed scans where possible to reduce false positives, and create separate scan policies for production (light footprint) versus staging (deeper checks). Exclude sensitive systems from aggressive checks or schedule them in maintenance windows; document these exceptions with justification and a risk-acceptance form. Store scanner configs (policy XML/JSON) as evidence so auditors see exactly what was run. Export raw scan results (XML/CSV) in addition to executive PDF summaries — raw data is often requested during audits.
Real-time detection: EDR, mail & web gateways, and SIEM
Real-time controls are your safety net for threats that periodic scans miss. Deploy an Endpoint Detection & Response (EDR) agent (e.g., Microsoft Defender for Business, CrowdStrike, or open-source Osquery + Fleet) on endpoints to detect suspicious processes, file writes, and persistence mechanisms. Pair EDR with real-time email scanning (gateway anti-malware) and a WAF for internet-facing web apps. Feed EDR and gateway alerts into a lightweight SIEM or cloud-native log analytics (Azure Sentinel, Splunk, Elastic) to correlate events and generate prioritized alerts. For small shops, use Microsoft 365 Defender or cloud provider-native tooling for cost-effective, integrated real-time telemetry.
Alerting, triage, and SLA examples
Create documented triage playbooks and SLAs tied to vulnerability severity: e.g., Critical - initial mitigation or containment within 72 hours and planned remediation within 7 days; High - planned remediation within 30 days; Medium/Low - tracked on normal patch cycles. Automate ticket creation (Jira/ServiceNow/GitHub Issues) from scanner and EDR alerts so every finding has a remediation workflow with owner, due date, and evidence of closure (patch deployment records, configuration change, or documented mitigations). Keep all tickets linked to the originating scan ID and CVE references to demonstrate chain-of-evidence during audit.
Audit readiness: documentation, retention, and demonstrable evidence
Audit-readiness is about repeatable evidence: maintain runbooks for each scan type (what tool, which policy, credentials used, scan target lists), keep immutable exports of reports (timestamped PDFs and raw XML/CSV), and store logs and ticket histories in an auditable repository (version-controlled or in a records system). Use immutable storage or WORM-like buckets for key evidence and retain it per contract or organizational policy (commonly 1–3 years); always check contract-specific retention. Prepare a compact "evidence pack" per assessment: inventory + last N scans per class + remediation ticket list + exception forms + screenshots of tool configurations and policies.
Real-world examples and small-business scenarios
Example 1: A 15-person engineering firm uses OpenVAS for weekly internal scans, schedules a paid external Qualys scan quarterly, and runs Microsoft Defender EDR on all laptops. A high CVSS 9.8 Apache vulnerability detected on their customer portal triggers an automated Jira ticket, immediate WAF rule addition (mitigation), and a planned patch within 48 hours; auditor evidence included the scan exports, Jira ticket history, and patch deployment logs. Example 2: A consulting shop without a full-time IT hire outsources periodic external scanning to an MSSP and uses Microsoft 365 Defender for real-time detection; when an infected contractor laptop was quarantined automatically, they produced EDR alert exports and the remediation ticket to show they fulfilled SI.L1-B.1.XV expectations.
Risks of not implementing a combined periodic + real-time program
Without paired periodic and real-time scanning you risk undetected vulnerabilities, slow detection of compromise, and missed contractual obligations under FAR 52.204-21 and CMMC expectations. Consequences include CUI exfiltration, regulatory noncompliance, contract termination, loss of business, and reputational damage. From an assessor's perspective, absence of documented scans, remediation evidence, and a repeatable process is as harmful as having vulnerabilities — it shows lack of control maturity.
Summary: build a simple, repeatable program that combines periodic credentialed internal scans, external scans, and real-time EDR/traffic monitoring; document policies, scanner configurations, triage playbooks, and SLAs; automate evidence collection and ticketing; and keep an audit evidence pack ready. For small businesses, leverage low-cost or cloud-native tools, outsource where necessary, and focus on demonstrable, time-stamped records to satisfy SI.L1-B.1.XV and associated Compliance Framework expectations.
