SI.L2-3.14.3 under NIST SP 800-171 Rev.2 / CMMC 2.0 Level 2 requires organizations handling Controlled Unclassified Information (CUI) to collect, retain, and report security-relevant logs and evidence in ways that support detection, response, and post-incident investigations — and this post gives small businesses a practical, step-by-step approach to implement, document, and produce that evidence during an assessment or incident.
What the Control Requires (practical interpretation)
At a practical level for a Compliance Framework implementation, SI.L2-3.14.3 means you must: identify what to log; ensure logs are collected centrally and protected; implement reporting workflows for anomalies or cyber incidents; and retain or package evidentiary artifacts (logs, alerts, reports, hashes, chain-of-custody) that demonstrate you can detect and respond to security events. It does not prescribe a single tool — it prescribes outcomes: consistent logging, reliable collection, protected storage, and reproducible evidence.
Implementation steps for a small business
Start with a simple, repeatable plan: 1) Inventory your log sources (Windows event logs, Linux syslog, firewall, VPN, cloud API logs like AWS CloudTrail/Azure Activity, EDR/antivirus, Office 365 audit logs). 2) Define a logging policy and retention schedule in your System Security Plan (SSP) and supporting policies (e.g., "security logs retained for 1 year; critical incident artifacts retained 3 years"). 3) Centralize collection using a SIEM, log aggregator, or cloud-native services (Splunk/Elastic/QRadar/Azure Sentinel/CloudWatch). 4) Harden log storage (append-only, access controls, encryption at rest/in transit). 5) Implement alerting and reporting rules mapped to your incident response playbooks.
Technical configuration details
Helpful technical specifics you can implement immediately: configure NTP on all hosts to ensure consistent timestamps; forward Windows Event Logs to a central collector via Winlogbeat (Elastic) or Windows Event Forwarding; configure syslog-ng/rsyslog for Linux hosts and network devices; enable AWS CloudTrail for all regions and write logs to S3 with Object Lock enabled; enable CloudWatch Logs subscription to a central SIEM. Ensure logs are formatted (JSON or CEF) for reliable parsing, and implement a retention tier: recent logs on fast storage (90 days), older logs in secure archival (S3 Glacier/Immutable object storage) with cryptographic hash checksums stored in metadata.
Evidence collection and preserving chain-of-custody
Auditors look for reproducible evidence: a CSV or JSON export of log entries tied to a specific incident; SIEM rule definitions and screenshots of triggered alerts; configuration dumps showing log forwarding is enabled; the SSP and policies referencing the logging controls; runbooks and incident reports with timestamps. For higher assurance, create an evidence bundle that includes exported logs, a manifest (listing files, timestamps, SHA-256 hashes), signed attestations from an authorized employee, and a log-access audit showing who viewed or exported the logs. Use write-once storage or cryptographic signing (GPG or HSM) on the evidence bundle to show it wasn’t altered.
Real-world small-business scenarios
Scenario A — Small DoD subcontractor on a budget: Use AWS CloudTrail + S3 with Object Lock for cloud resources; deploy Wazuh (open-source) to collect Windows/Linux logs and forward to an Elastic Stack running on a single EC2 with encryption enabled. Document your retention policy in the SSP and create a periodic “evidence export” runbook that exports a week of logs, generates SHA-256 checksums, and uploads to an immutable S3 folder. Scenario B — On-premises shop with a managed service provider (MSP): Configure the MSP to forward firewall and domain controller logs to the MSP's SIEM with a contractual clause requiring logs retention and evidence exports; require the MSP to provide signed incident reports and periodic audit exports for your POA&M.
Reporting workflows and regulatory touchpoints
Define internal reporting thresholds (e.g., failed logon spikes, data exfiltration indicators) and map them to an incident reporting workflow: detection → triage → internal notification → external reporting. For DoD contractors, combine this with DFARS incident reporting obligations (e.g., report confirmed compromises affecting CUI within the required timeframe). Maintain templates for incident reports that include timeline, affected assets, evidence artifacts (with checksums), mitigation steps, and disposition — these templates become evidence during assessments.
Compliance tips and best practices
Practical compliance tips: include logging and evidence procedures in your SSP and POA&M; maintain playbooks and show evidence of tabletop exercises; automate evidence collection with scripts that export logs and compute hashes to avoid ad-hoc, error-prone evidence packages; perform periodic integrity checks on backups and archived logs; restrict access to log repositories using least privilege and multi-factor authentication; and regularly validate that log sources are still forwarding data (use heartbeat alerts).
Risk of non-implementation
Failing to implement SI.L2-3.14.3 exposes you to several risks: undetected intrusions that can lead to CUI exfiltration, inability to prove compliance during audits, contract termination or loss of future contracts, and potential regulatory penalties. Operationally, without reliable logs and evidence you cannot reconstruct attacks, delaying containment and increasing recovery costs and reputational damage.
Summary: For Compliance Framework adherence to SI.L2-3.14.3, focus on inventorying log sources, centralizing and protecting logs, documenting policies and retention in your SSP, automating evidence collection with integrity checks, and maintaining clear reporting workflows; small businesses can meet these requirements using a mix of cloud-native services, open-source tooling, and well-documented processes that produce reproducible evidence for audits and incident response.
