Affordable CMMC Compliance Tools for Small Business — The $22K/Year Stack That Works

The CMMC consulting market sells $200K/year tooling stacks to 20-person contractors. Most of it is overkill. This is the honest sub-$25K/year stack that satisfies Level 2 for a small federal contractor — by category, with vendor names, real pricing, and the controls each tool covers.

The full stack at a glance

Category	Tool	Annual Cost (20 users)	NIST 800-171 controls covered
Email + File + Teams	Microsoft 365 GCC E3	$8,400	Major portions of 3.1, 3.5, 3.13, 3.14
Endpoint management	Intune (included with M365 GCC)	$0	3.4 (Configuration Management)
MFA / SSO	Entra ID Government (included)	$0	3.5.3
Conditional Access	Entra ID (included)	$0	3.1, 3.5
Vulnerability scanning	Tenable Nessus Professional	$4,000	3.11.2, 3.14.1
Security awareness training	KnowBe4 small-business	$2,000	3.2.1, 3.2.2
SIEM / log aggregation	Microsoft Sentinel pay-as-you-go	$2,000	3.3 (Audit and Accountability)
FIPS-validated VPN	Tailscale Enterprise	$2,000	3.13.1, 3.13.5
Background screening	Sterling or HireRight per-check	$1,000 (20 × $50)	3.9.1
DCAA-compliant accounting + audit trail	FieldLedger + QBO	$2,900	Major portions of 3.3 (audit trail half), all of DCAA layer
TOTAL		~$22,300	All 14 NIST 800-171 families substantially covered

This is the cheapest defensible stack. Below this number, you're cutting controls a C3PAO will catch.

Microsoft 365 GCC E3 — the foundation

Cost	$35/user/mo × 20 = $8,400/yr
Controls covered	3.1.1, 3.1.2, 3.1.5, 3.5.1, 3.5.3, 3.5.7, 3.13.1, 3.13.5, 3.13.8, 3.14.1, 3.14.2, 3.14.6, plus the audit-log half of 3.3
Inheritance value	M365 GCC is FedRAMP Moderate / High authorized — you inherit the underlying CSP controls

This is the single largest budget line and the highest-leverage decision in the stack. M365 GCC pulls 30+ NIST 800-171 controls from "manual implementation" to "platform-inherited."

What's included:

• Email with FIPS-validated TLS in transit and AES-256 at rest
• SharePoint and OneDrive for File storage with same crypto
• Teams for collaboration
• Entra ID Government tenant (separate from commercial)
• Intune for endpoint management
• Defender for Endpoint (basic)
• Audit logging across the M365 surface
• Conditional Access policies

What's NOT included (and you'll need separately):

• SIEM beyond M365 native logging (Sentinel pay-as-you-go fills this)
• Vulnerability scanning of your endpoints and cloud (Tenable fills this)
• Application-specific audit logging for non-M365 systems (FieldLedger covers accounting; other systems need their own)

Intune — endpoint management included

Cost	$0 incremental (included with M365 GCC E3)
Controls covered	3.4.1, 3.4.2, 3.4.6, 3.4.7, 3.4.8, 3.4.9

Configuration Management is family 3.4. Without managed endpoints, you cannot pass these controls. With Intune (included), you can.

What you do with Intune:

• Push hardening baselines to Windows / macOS
• Enforce disk encryption (BitLocker / FileVault)
• Block unauthorized software installation
• Manage mobile devices (containerization for CUI work)
• Inventory software installed
• Enforce screen lock and timeout

This eliminates BYOD for CUI work — every device touching CUI is enrolled in Intune. Most SMBs find this more operationally workable than they expect; if your existing fleet is under 30 devices, enrollment is a 1–2 day project.

Entra ID Government for MFA + Conditional Access

Cost	$0 (included with M365 GCC)
Controls covered	3.5.3, 3.5.4, 3.5.5, 3.5.6, 3.5.7, 3.5.8, 3.5.9, 3.5.10, 3.5.11

Family 3.5 (Identification and Authentication) — 11 controls. Entra ID Government covers most of them.

What to enable:

• MFA enforcement on every account (no exceptions for service accounts)
• Conditional Access policies blocking access from non-managed devices
• Password complexity meeting NIST 800-63B (12+ chars, no rotation requirement)
• Account lockout after 10 failed attempts
• Session timeout (30 min idle)

Two enforcement gotchas:

• Service accounts often skip MFA. Use managed identities or workload identities instead.
• Legacy authentication protocols (SMTP basic auth, etc.) bypass MFA. Disable them at the tenant level.

Tenable Nessus Professional for vulnerability scanning

Cost	$4,000/yr
Controls covered	3.11.2, 3.11.3, 3.14.1, 3.14.6

Vulnerability scanning is required by 3.11.2 and not included in M365. Tenable Nessus Professional is the SMB standard at $4K/yr per scanner. For a 20-person contractor, one scanner covers your entire footprint.

Alternative options:

• Qualys — comparable, often pricier for SMB
• Rapid7 InsightVM — strong, $5K–$10K/yr typical
• OpenVAS / Greenbone Community — free but operational overhead
• Microsoft Defender for Cloud — tied to Azure, weaker for hybrid environments

Run scans monthly. Document remediation in your POA&M. C3PAO will sample the scan history.

KnowBe4 for security awareness training

Cost	$2,000/yr (small-business tier)
Controls covered	3.2.1, 3.2.2, 3.2.3

Family 3.2 has 3 controls — all three boil down to "annual security training for everyone with CUI access." KnowBe4's small-business tier handles this with monthly micro-trainings, simulated phishing, and tracking dashboards.

Alternatives:

• Curricula — comparable, often $1,500/yr small-business
• Hoxhunt — focused on phishing simulation, $2K–$5K/yr
• Internal training (PowerPoint + signed acknowledgement) — $0 if you build the content. Higher operational overhead.

The C3PAO will ask for training completion records. KnowBe4 makes this trivial.

Microsoft Sentinel for SIEM / log aggregation

Cost	$2,000/yr at modest log volume (pay-as-you-go)
Controls covered	3.3.1, 3.3.2, 3.3.3, 3.3.4, 3.3.5, 3.3.6

Family 3.3 (Audit and Accountability) requires logging across all CUI-touching systems with retention and review. M365's native logging is good but lives in M365. Sentinel pulls logs from M365, Intune, your on-prem systems (if any), and third-party tools into a central queryable repository.

Pay-as-you-go pricing means you only pay for ingested log volume. For a 20-person contractor, monthly log volume is typically 5–20 GB, which lands at $50–$200/mo.

Alternatives:

• Splunk Cloud Government — better than Sentinel for some use cases, much pricier ($15K+/yr typical)
• Datadog (FedRAMP variant) — strong for monitoring + logging, $5K–$15K/yr
• Elastic Stack self-hosted — free software, operational overhead

Sentinel is the cheapest defensible path because it's already in your Azure/M365 GCC tenant and pays-as-you-go.

Tailscale Enterprise for FIPS-validated VPN

Cost	$2,000/yr (20 users at small-business tier)
Controls covered	3.13.1, 3.13.5, 3.13.6

Family 3.13 (System and Communications Protection) requires network boundary protection and FIPS-validated cryptography. For a remote-first 20-person contractor, the VPN is the boundary.

Tailscale Enterprise has a FIPS-validated cryptographic module and Conditional Access integration. Configuration is dramatically easier than traditional VPNs (OpenVPN, Cisco AnyConnect).

Alternatives:

• OpenVPN Access Server with FIPS module — $300–$2,000/yr depending on deployment
• Cisco AnyConnect — enterprise-priced, often $10K+/yr
• Microsoft Always-On VPN — included if you're deep in M365 GCC, configuration overhead

If your team is exclusively in M365 GCC and uses Conditional Access for everything, you may not need a separate VPN. Most contractors have at least one non-M365 system that needs protected access — that's where the VPN earns its keep.

Sterling or HireRight for background screening

Cost	$50–$80 per check, ~$1,000/yr for 20 hires/turnover
Controls covered	3.9.1, 3.9.2

Family 3.9 (Personnel Security) — 2 controls. Background screening for everyone with CUI access. Use Sterling or HireRight for new hires; document the screening in the personnel file.

Don't forget:

• 1099 contractors with CUI access need screening too
• Subcontractor staff with CUI access need verification (the sub does the screening; you confirm)
• Re-screening on role changes that expand CUI access

FieldLedger + QuickBooks Online for accounting + audit trail

Cost	$149/mo + $90/mo = $2,868/yr
Controls covered	5 of the 9 controls in family 3.3 (for accounting subsystem)

DCAA-compliant timekeeping and accounting produces exactly the evidence shape NIST 3.3 requires: timestamped entries, user attribution, before/after value capture on edits, immutable audit log, retention for the contract period.

This is dual-purpose value — same system that satisfies DCAA also satisfies NIST 3.3 for the accounting layer. You don't pay twice for two audit-log systems.

What it doesn't cover:

• Audit logging for email (M365 GCC handles this)
• Audit logging for file storage (M365 GCC)
• Audit logging for non-accounting applications (each app needs its own)

What you can skip below $22K/year

If budget is tighter:

Skip Sentinel ($2K savings). Use M365 GCC native logging only. Lose some 3.3 family points but stay defensible at Level 2 Self-Assessment. Not enough for Level 2 Certified.

Skip Tailscale ($2K savings). If your entire stack is in M365 GCC and you use Conditional Access exclusively, you may not need a separate VPN. Verify with the C3PAO during scoping.

Skip KnowBe4 ($2K savings). Self-built annual training with signed acknowledgement satisfies 3.2 if documented. Higher operational overhead, lower polish.

Realistic floor: ~$15K/yr. Below that, you're cutting controls.

What you cannot skip

M365 GCC. The single highest-leverage spend. Without it, you're manually implementing 30+ controls that GCC inherits.

MFA enforcement. 3.5.3 is POA&M-prohibited at Level 2 Certified. Either implement or fail.

Vulnerability scanning. 3.11.2 is non-negotiable. Tools cost what they cost.

Background screening. 3.9.1 is non-negotiable. $50/check is the floor.

SSP/POA&M discipline. Free if you do it yourself, $15K–$40K if you outsource. Either way, you can't skip it.

What about the $200K/year stack pitches

You'll get sales calls offering:

• Splunk Enterprise Cloud ($30K+/yr)
• CrowdStrike Falcon Government ($20K+/yr)
• Palo Alto Prisma Cloud ($25K+/yr)
• Privileged Access Management platforms ($30K+/yr)
• Insider Threat Detection ($15K+/yr)

These are all good products. Most are unnecessary at the 20-employee scale. The CMMC controls don't require them — they suggest capabilities those products provide, but the sub-$25K stack above satisfies the controls directly.

The exception: if your contracts move you into Level 2 Certified for higher-sensitivity CUI or you grow beyond 50 employees, some of these become economic. Until then, the basic stack is enough.

What to do this week

1. Audit your current stack against this list. Each missing line is a control gap.

2. Start the M365 GCC migration if you're on commercial M365. This is the longest pole; don't delay.

3. Get pricing quotes on Tenable, KnowBe4, and Sentinel. Lock pricing for budget planning.

4. Confirm your background screening process. If you're not screening 1099s with CUI access, fix that.

5. Document each tool in your SSP. A C3PAO reads your SSP first; the more your tools map cleanly to control numbers, the faster the assessment runs.

Related reading

• CMMC 2.0 compliance for sub-50-employee contractors
• CMMC Level 1 vs Level 2 checklist
• C3PAO assessment cost and timeline
• NIST 800-171 compliance for small government contractors
• CUI handling for small government contractors