CMMC Compliance

Overview

The Cybersecurity Maturity Model Certification (CMMC) 2.0 is a U.S. Department of Defense (DoD) program that requires all contractors, subcontractors, and suppliers who handle Federal Contract Information (FCI) or Controlled Unclassified Information (CUI) to achieve certification. Whether your organization works directly with the DoD or as part of the Defense Industrial Base (DIB) supply chain, demonstrating compliance is mandatory to maintain contract eligibility.

Achieving CMMC compliance is not guaranteed as it depends on proper configuration, policies, and broader organizational practices outside the software’s scope. However, this document outlines how Mattermost’s features can help U.S. Department of Defense contractors and subcontractors address specific Level 2 requirements.

Access Control and Identity Management

Mattermost supports robust identity and access management to ensure that only authorized users access the system and that they only see data permitted for their role. Key capabilities include:

Single Sign-On (SSO) Integration: Mattermost integrates with enterprise identity providers via SAML 2.0, OpenID Connect, and AD/LDAP. This allows you to centrally manage user accounts and enforce enterprise authentication policies. Only users provisioned in your directory (and assigned to the Mattermost service) can log in. This helps satisfy access control requirements to “limit system access to authorized users” (AC 3.1.1) using vetted corporate identities.

Role-Based Access Control (RBAC): Granular permissions in Mattermost ensure users can perform only the actions permitted for their role. For example, regular users cannot perform administrative functions, and guest accounts have restricted access to specific channels. Administrators can configure team-wide and channel-specific roles/permissions so that users only access data and functions needed for their duties. This supports the principle of least privilege (AC 3.1.5) and limits users’ actions to authorized functions (AC 3.1.2, AC 3.1.7).

Group-Based Access Management: Mattermost AD/LDAP Group Sync automates user provisioning and de-provisioning. Users can be added or removed from Mattermost teams/channels based on their directory group membership. This ensures timely removal of access when personnel change roles or leave (addressing account management aspects of AC 3.1.1) and helps enforce separation of duties (AC 3.1.4) by aligning channel access with organizational roles.

Session Management and Timeout: Mattermost administrators can define session security settings, including session idle timeouts and session lifetime. Sessions can be automatically invalidated after a period of inactivity or on demand. By limiting session duration and requiring re-authentication, Mattermost reduces the risk of unauthorized access via unattended sessions (helps address AC 3.1.6 for session lock and IA 3.5.2 for session control). Failed login attempt thresholds can also be set (e.g. lock out after X failed attempts) to mitigate brute-force attacks, aligning with AC 3.1.8.

User Agreement and Access Approval: Mattermost Enterprise supports a Custom Terms of Service banner that users must accept upon first login. This can be used to remind users of acceptable use policies or consent to monitoring, indirectly supporting training/awareness requirements and ensuring users acknowledge security terms before accessing CUI.

Authentication and Multi-Factor Authentication (MFA)

Secure authentication is critical for protecting Controlled Unclassified Information (CUI). Mattermost offers several features to strengthen user authentication in alignment with CMMC requirements:

Unique User Identification: Each Mattermost user has a unique account (username/email), satisfying the need for unique IDs (IA 3.5.1). Administrators can deactivate accounts that are found to be generic or shared, and when integrated with enterprise SSO or LDAP, organizational policies can prevent shared account use.

Password Policy Enforcement: For built-in authentication, Mattermost administrators can enforce strong password requirements (minimum length, complexity). This helps meet IA 3.5.2 by requiring robust passwords and reducing the risk of credential compromise.

Multi-Factor Authentication: Mattermost supports MFA for all user accounts. In self-hosted deployments, admins can enable and enforce TOTP-based MFA (e.g. requiring a one-time code from Google Authenticator during login). When Mattermost is integrated with SSO (SAML/OIDC), you can leverage the IdP’s MFA policies (e.g. CAC/PIV or OTP) for Mattermost logins. Requiring two factors for authentication aligns with CMMC practice IA 3.5.3, adding an extra layer of verification to protect accounts even if passwords are compromised.

Account Lockout and Recovery: Mattermost can limit failed login attempts and lock accounts after a specified number of failures, helping to thwart brute-force attacks (IA 3.5.3, additional aspect). It also provides options for secure password reset or administrator-issued password resets to support account recovery while maintaining security controls.

Audit Logging and Accountability

CMMC Level 2 (NIST 800-171) places heavy emphasis on audit logging and the ability to track and monitor system activity (Audit & Accountability, AU 3.3.x controls). Mattermost provides built-in logging and monitoring features that help meet these requirements:

System and Application Audit Logs: Mattermost records server and application events in an audit log (JSON format). This includes security-relevant events such as logins, account creations, permission changes, server configuration changes, and more. Enterprise editions can send logs to external syslog or monitoring systems in real time. These logs provide the evidence needed for AU.3.3.1 (“generate audit records for user/activity”) and support analysis of incidents.

Message History Retention: By default, Mattermost retains a complete history of all messages (including edits and deletions) and file uploads in the database. Even if a user deletes a message in the application, the data is still preserved in the backend (unless a retention policy is in place). This ensures actions are traceable to individuals (AU 3.3.2) and meets requirements to retain and archive audit data. Administrators can also disable users’ ability to edit or delete messages, guaranteeing an unalterable record of conversation content for compliance purposes (useful for investigations and meeting audit retention requirements).

Compliance Export and Electronic Discovery: Mattermost’s Compliance Export feature can automatically export message history and metadata on a scheduled basis. This helps organizations produce chat records for audits, e-discovery, or long-term archival outside the application (relevant to AU 3.3.3 on audit record retention and review). Additionally, integration with third-party archiving and e-discovery tools is supported (e.g. Smarsh/Global Relay), enabling centralized analysis of communications for compliance.

Automated Monitoring and Alerts: Administrators can generate daily compliance reports of Mattermost activity or use the audit data for anomaly detection. Mattermost supports integration with Security Information and Event Management (SIEM) systems by sending logs to a syslog or via the API. This allows organizations to correlate Mattermost events with other security data and receive alerts on suspicious behavior (e.g. multiple failed logins, unexpected user account changes), supporting AU 3.3.4 and RA 3.11.2 (continuous monitoring and risk assessment). Mattermost’s audit log can thus feed into your incident monitoring process for rapid detection of issues.

Protection of Audit Information: Access to Mattermost logs is restricted to system administrators – regular users cannot view or tamper with audit records. Logs written to files on the server can be further protected by OS-level access controls. This aligns with AU 3.3.5 (prevent unauthorized access/modification of audit records). Additionally, if using Mattermost Cloud or an external log aggregator, you should apply appropriate controls to those environments to safeguard the logs.

Incident Response and Incident Collaboration

Under CMMC Level 2, companies must establish and maintain an effective Incident Response (IR) capability (IR 3.6.1–3.6.3). Mattermost is a valuable tool for incident response planning, execution, and documentation:

Incident Playbooks: Collaborative workflows managed through Mattermost Playbooks allow teams to codify their incident response plans and checklists directly in the platform. For example, you can create a playbook for “Cyber Incident Response” that automatically spins up a dedicated incident channel, assigns tasks to responders, notifies stakeholders, and tracks investigation steps when an incident is declared. This ensures a standardized response process, fulfilling the requirement to establish an operational incident-handling capability (IR 3.6.1) with defined preparation, detection, containment, and recovery steps.

Dedicated Incident Channels: Mattermost enables the creation of private, invite-only channels for incident responders. During an incident (e.g. a network breach or system outage), teams can coordinate in a secure Mattermost channel that is isolated from potentially compromised systems. Mattermost’s self-hosted or air-gapped deployment options allow it to serve as an out-of-band communication) platform if primary systems or networks are affected. This approach helps contain incidents by preventing adversaries from monitoring or disrupting incident comms, and supports IR 3.6.1’s requirement for effective coordination during an incident.

Real-Time Notifications and Integrations: Mattermost can integrate with monitoring tools and security systems to streamline detection and response. For instance, a SIEM or IDS can post an alert to a Mattermost channel (via webhooks or integrations) to notify the team of a potential incident. Mattermost Playbooks support automated incident notifications – triggering alerts to responders when certain conditions are met. This real-time alerting and centralization of incident communication assists with prompt detection and reporting of incidents (IR 3.6.2). Team members can discuss and analyze the threat in Mattermost, accelerating triage.

Task Tracking and Documentation: With Mattermost Playbooks and Boards, each incident response run can have an associated checklist of tasks (e.g. Identify affected systems, Collect logs, Eradicate malware, etc.) and an owner for each task. Responders check off tasks as they are completed, and all actions are timestamped. This creates an auditable timeline of the incident. All discussion in the incident channel, file attachments (like forensic screenshots), and timeline of actions are preserved. This comprehensive documentation of incidents satisfies IR 3.6.2’s mandate to track and report incidents to appropriate officials, and helps during post-incident analysis. Mattermost also facilitates post-incident reviews by enabling teams to add retrospective notes in the channel or Playbook run after resolution. These records can be exported as needed for reporting to DoD or other authorities.

Testing Incident Response: Mattermost can be used to conduct incident response drills or tabletops. Teams can simulate incidents by running playbooks in Mattermost (e.g. a planned exercise) to verify that everyone receives notifications and follows the procedures. This helps meet IR 3.6.3 (test the incident response capability) by providing a platform to perform and document response tests. Over time, playbook analytics and metrics (e.g. average time to resolution) allow you to gauge improvements in IR performance.

By leveraging Mattermost for incident response, organizations create a central hub for managing incidents from initial alert to post-mortem. This directly supports CMMC Level 2 requirements to have an established, tested incident response process and to document and report incidents in a timely manner.

Communications Protection and Data Security

CMMC Level 2 includes controls to safeguard information during storage and transmission (System & Communications Protection, SC 3.13.x) and to limit unauthorized information flows. Mattermost offers multiple features to protect data and control communications:

Encryption in Transit: All Mattermost client-server communication can be encrypted using TLS (Transport Layer Security). When configured with HTTPS, Mattermost encrypts data in transit between the server and clients (web, desktop, mobile), preventing eavesdropping on CUI being discussed or transferred. This meets the requirement to protect CUI on networks by encrypting it during transmission (SC 3.13.8). Mattermost supports modern TLS protocols and ciphers; administrators should configure TLS per DoD guidelines (e.g. FIPS 140-2 validated cryptographic modules where applicable) to fully satisfy this control.

Encryption at Rest: Mattermost supports encryption of data at rest through enterprise database and storage configurations. The application can be deployed on encrypted file systems or use encrypted storage backends. For instance, if using Amazon S3 for file storage, Mattermost Enterprise can enable server-side encryption with S3-managed keys. If using a self-hosted database, administrators can enable disk encryption or TDE on the database server. By encrypting the Mattermost database and storage drives, organizations add a layer of protection for CUI stored in chat messages and files, helping to meet SC 3.13.16 (protect confidentiality of CUI at rest) and MP 3.8.3 (media sanitization if disks are disposed). Mattermost documentation encourages regular key rotation and secure key management for encryption at rest.

Network Access Control and Segmentation: Mattermost can be deployed in a manner that controls network access to the system. In self-hosted deployments, organizations often place Mattermost servers in a secure enclave or DMZ with firewalls controlling ingress/egress. For cloud deployments, Mattermost Cloud offers IP allowlisting (Enterprise plan) to restrict access to known IP ranges. These configurations address SC 3.13.1 and SC 3.13.2 by allowing Mattermost to reside within a protected network segment and ensuring only trusted networks or VPN users can reach it. Additionally, within Mattermost, data is segmented by Teams and Channels – you can create separate teams for different projects or clearance levels, and mark channels as private to restrict membership. This “micro-segmentation” of conversations ensures that sensitive discussions (e.g. about a specific CUI program) are isolated to authorized individuals, reducing inadvertent information exposure.

Self-Hosted and Air-Gapped Deployment: Unlike many collaboration tools, Mattermost can be fully self-hosted on-premises or in a sovereign cloud, giving organizations complete control over data locality. DoD contractors can deploy Mattermost in an air-gapped environment with no outside internet connectivity if required. This supports compliance when handling CUI that cannot be exposed to external systems. By keeping Mattermost within the same secured IT boundary as other CUI systems, contractors address concerns of SC 3.13.5 (isolate system components from external access). Mattermost’s deployment flexibility (on-prem, GovCloud, etc.) allows alignment with DoD requirements (e.g. hosting at IL4/IL5 for sensitive data, if using cloud infrastructure). All user data resides in the infrastructure you control, aiding data sovereignty and compliance with any FedRAMP or ITAR restrictions that may apply in addition to CMMC.

Data Loss Prevention Measures: While Mattermost does not natively include a full DLP suite, administrators can enforce certain restrictions to prevent unauthorized sharing or retention of data. For example, public link sharing (for files) can be disabled or restricted, ensuring that shared files are not exposed to untrusted users. File Upload Settings and Plugin Whitelisting allow you to control what types of files can be shared or which integrations are allowed, supporting SC 3.13.4 (control of information flows). Additionally, the Push Notification contents can be configured to omit message text, so that if mobile push notifications are used, they do not leak sensitive message content to device lock screens or external services. For more advanced DLP, Mattermost’s open APIs and webhooks enable integration with external DLP solutions or content filtering systems (e.g. a script could detect and remove messages containing certain keywords or PII). These measures help fulfill AC 3.1.3 / SC 3.13.4 by controlling the flow of CUI and preventing it from leaving authorized channels.

Sensitive Information Controls: System-wide banners can display CUI handling notices such as “⚠️ This system contains CUI. Use authorized accounts only. All activity is monitored.” Supports AC.L2-3.1.9, AT.L2-3.2.1, IR.L2-3.6.2, and MP.L2-3.8.2. As well as channel-specific banners can be used to flag channels containing CUI or incident response data, reinforce workflow integrity, or restrict data sharing. Supports AC.L2-3.1.3, MP.L2-3.8.2, AU.L2-3.3.1/3.3.2, and SC.L2-3.13.4.

Antivirus Scanning: To address system integrity requirements (SI 3.14.5 for scanning files for malware), Mattermost can integrate with antivirus tools. A ClamAV plugin is available that scans files uploaded to Mattermost for viruses and malware. When enabled, this helps ensure that malicious files are detected and quarantined, protecting users and meeting the intent of controls on detecting and protecting against malware (SI 3.14.4 and SI 3.14.5). Administrators should also keep the Mattermost server host up-to-date with security patches and monitor for vulnerabilities (SI 3.14.1/3.14.2), as part of overall system integrity maintenance.

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