Meeting FAR 52.204-21 and CMMC 2.0 Level 1 requirements for basic safeguarding often comes down to selecting and correctly configuring antivirus (AV) and endpoint detection and response (EDR) tools so that covered contractor information (FCI) is protected against malicious code; this post gives small businesses practical, technical, and compliance-focused steps to choose, deploy, tune, and validate an AV/EDR solution that helps satisfy the Compliance Framework control SI.L1-B.1.XIV.
Understand the requirement and scope
FAR 52.204-21 requires contractors to provide basic safeguarding of contractor information on contractor systems and networks; CMMC 2.0 Level 1 includes practices for protecting against malicious code. For the Compliance Framework this maps to a practice requiring malware protection and active endpoint monitoring. First, inventory the systems that process, store, or transmit FCI and scope endpoints (workstations, laptops, servers, contractors’ devices) and cloud-hosted instances you must protect. Without a complete inventory you cannot prove controls are consistently applied.
How to choose an AV/EDR solution
For small businesses choose a solution that balances detection capability, manageability, and cost. Key selection criteria: (1) Signature plus behavior-based detection (EPP + EDR), (2) cloud-managed console with role-based access and MFA, (3) automated updates and threat intelligence feeds, (4) ability to centrally configure policies, quarantine, and event retention, (5) lightweight agent footprint for mixed OS environments (Windows, macOS, Linux), (6) telemetry/API integration with your logging or SIEM, and (7) vendor support and proven detection of targeted threats. Examples: Microsoft Defender for Business + Defender for Endpoint, CrowdStrike Falcon, SentinelOne, and Bitdefender GravityZone are commonly chosen by small contractors. If budgets are tight, prioritize a cloud-managed EDR with built-in telemetry over legacy signature-only AV.
Real-world small business scenario
Example: A 25-employee subcontractor handling FCI uses a cloud ERP and about 20 Windows laptops. Practical choice: Microsoft Defender for Business (or Defender for Endpoint with a Defender for Business license upgrade) because it integrates with Microsoft 365, has low agent overhead, and includes centralized management. If the team lacks security operations capability, add a managed detection and response (MDR) add-on or partner for 24/7 escalation and quarterly threat hunts; this keeps costs predictable while meeting detection requirements.
Essential configuration and hardening steps
Configure the chosen AV/EDR to demonstrate consistent, auditable protection. Minimum technical settings to implement: enable real-time protection, enable cloud-delivered protection and automatic sample submission, turn on tamper protection, enforce automatic signature and engine updates (minimum hourly/real-time), enable full-disk and script protection, configure automatic quarantine for high-confidence detections, and set scheduled universal scans (quick scans daily, full weekly). For EDR, set telemetry/collection level to “High” or “Full” for endpoints that handle FCI and ensure suspicious process/file collection is active for triage. Centralize policy deployment through the console and enable role-based admin accounts protected with MFA.
Logging, retention, and evidence for auditors
FAR/CMMC reviewers will want to see evidence that malware controls are operational. Forward EDR alerts and prevention events to a central log store or SIEM (can be cloud-hosted). Retain endpoint detection logs and quarantine records for a defined retention (recommended minimum 90 days for Level 1 evidence; extend per contract obligations). Establish alerting for high-severity detections to a monitored inbox or ticketing system and log incident response actions. Document the policy baseline, agent install inventory, and automated update schedule to present during assessment.
Tuning, exceptions, and ongoing operations
Tune to reduce false positives while avoiding blind spots: minimize exclusions (document and authorize any you create), use allowlisting sparingly, and maintain a change log for exclusions. Implement a quarterly review process: update signatures, review detections, remove stale exclusions, and validate online status of all agents. For small teams, define an escalation playbook: what constitutes a high-severity endpoint compromise, who to notify, and when to engage MDR or an incident response vendor. Automate containment where possible (isolate endpoint from network on confirmed host compromise) to limit lateral movement.
Risks of not implementing properly
Failing to choose or correctly configure AV/EDR exposes FCI to ransomware, credential theft, and data exfiltration. Beyond data loss, consequences include contract termination, loss of future contracts, investigation costs, reputational damage, and potential reporting obligations. Technical risks include undetected persistent threats, lateral movement to servers storing FCI, and ineffective audits due to missing logs and weak telemetry. Noncompliance also increases the likelihood of failing CMMC assessments or not meeting FAR contract clauses.
Compliance tips and best practices
Practical tips: maintain an up-to-date asset inventory; standardize images with preinstalled, configured agents; enforce least privilege and application control; segregate FCI to minimize scope; use endpoint backups and test recovery procedures; validate agent coverage after major OS or vendor updates; and keep a written policy explicitly stating AV/EDR settings and retention. Use baseline tests (e.g., run EICAR test files in a controlled manner) and table-top exercises to prove detection and response workflows. For procurement, require vendor evidence of independent AV/EDR tests and ask for SLA metrics on detection and response for MDR contracts.
Summary: To satisfy FAR 52.204-21 and CMMC 2.0 Level 1 SI.L1-B.1.XIV, a small business should select a modern EPP+EDR solution with centralized management, enable real-time protections and telemetry, enforce automated updates and tamper protection, forward logs for retention and review, and document policies and evidence of operation; combined with regular tuning, testing, and a simple incident playbook, these steps both reduce risk and produce the artifacts assessors need to demonstrate compliance.
