MongoDB Secure Deployment & Hardening Guide
CIS-aligned hardening guidance and control-by-control implementation notes
1. Scope and assumptions
This guide provides practical hardening guidance aligned to the CIS-style control list. It is written for infrastructure and platform teams who deploy and operate MongoDB in production.
Baseline assumptions:
· MongoDB 6.x/7.x on Linux (systemd).
· Standalone and replica set deployments; sharding notes included where relevant.
· Security baseline includes access control, TLS in transit, least privilege roles, and central logging.
2. Deployment baseline
Before applying control-specific hardening, establish a secure baseline:
· Place MongoDB on private networks; do not expose database ports to the Internet.
· Use configuration management for mongod.conf and systemd overrides; keep changes reviewed and tracked.
· Separate application identities from human administrator identities.
· Ensure backup and restore procedures are documented and regularly tested.
3. Control-by-control hardening guidance
The following sections map each control to recommended implementation steps, validation methods, and operational notes. Use this as a deployment checklist and as evidence guidance for audits.
Audit Logging
5.1 — Ensure that system activity is audited
Severity: High
Automatable: Automated
Check type: (not specified)
Implementation
· Enable audit logging for authentication events, administrative actions, and role changes where licensing/support allows.
· Forward logs to your central logging/SIEM with integrity protections and access controls.
· Apply log retention aligned to policy and regulatory requirements; protect logs from tampering.
Validation
· Confirm audit configuration is present (mongod.conf) and events are generated during controlled test actions.
· Verify log forwarding is active and logs are searchable with expected fields.
Operational notes
· Audit logging increases IO; size disks and retention accordingly, especially on high-throughput clusters.
5.2 — Ensure that audit filters are configured properly
Severity: High
Automatable: Manual
Check type: (not specified)
Implementation
· Enable audit logging for authentication events, administrative actions, and role changes where licensing/support allows.
· Forward logs to your central logging/SIEM with integrity protections and access controls.
· Apply log retention aligned to policy and regulatory requirements; protect logs from tampering.
Validation
· Confirm audit configuration is present (mongod.conf) and events are generated during controlled test actions.
· Verify log forwarding is active and logs are searchable with expected fields.
Operational notes
· Audit logging increases IO; size disks and retention accordingly, especially on high-throughput clusters.
5.3 — Ensure that logging captures as much information as possible
Severity: High
Automatable: Automated
Check type: (not specified)
Implementation
· Enable logging and configure rotation to prevent disk exhaustion.
· Monitor key metrics: connections, replication lag, cache pressure, disk utilization, and slow queries.
· Alert on security-relevant events: failed logins, privilege changes, unexpected restarts, and listener changes.
Validation
· Confirm logs rotate and retention prevents unbounded growth.
· Validate monitoring and alerts trigger during controlled tests.
5.4 — Ensure that new entries are appended to the end of the log file
Severity: Low
Automatable: Automated
Check type: (not specified)
Implementation
· Enable logging and configure rotation to prevent disk exhaustion.
· Monitor key metrics: connections, replication lag, cache pressure, disk utilization, and slow queries.
· Alert on security-relevant events: failed logins, privilege changes, unexpected restarts, and listener changes.
Validation
· Confirm logs rotate and retention prevents unbounded growth.
· Validate monitoring and alerts trigger during controlled tests.
Authentication
2.1 — Ensure Authentication is configured
Severity: Critical
Automatable: Automated
Implementation
· Enable access control (authorization) and require authentication for all users and services.
· Use least-privilege roles: separate app users from admin users; avoid using built-in root for applications.
· Prefer SCRAM-SHA-256 for password auth; enforce strong password policy and rotation where feasible.
· For privileged/admin access, consider x.509 or an external identity provider (LDAP/Kerberos) where supported.
Validation
· Confirm security.authorization is enabled and unauthenticated operations are rejected.
· Review roles assigned to application accounts; validate they only have required actions on required DBs/collections.
Operational notes
· Create break-glass admin access with strong controls (MFA at the jump host, approvals, and tight audit).
2.2 — Ensure that MongoDB does not bypass authentication via the localhost exception
Severity: Critical
Automatable: Automated
Implementation
· Enable access control (authorization) and require authentication for all users and services.
· Use least-privilege roles: separate app users from admin users; avoid using built-in root for applications.
· Prefer SCRAM-SHA-256 for password auth; enforce strong password policy and rotation where feasible.
· For privileged/admin access, consider x.509 or an external identity provider (LDAP/Kerberos) where supported.
Validation
· Confirm security.authorization is enabled and unauthenticated operations are rejected.
· Review roles assigned to application accounts; validate they only have required actions on required DBs/collections.
Operational notes
· Create break-glass admin access with strong controls (MFA at the jump host, approvals, and tight audit).
2.3 — Ensure authentication is enabled in the sharded cluster
Severity: Critical
Automatable: Automated
Implementation
· Enable access control (authorization) and require authentication for all users and services.
· Use least-privilege roles: separate app users from admin users; avoid using built-in root for applications.
· Prefer SCRAM-SHA-256 for password auth; enforce strong password policy and rotation where feasible.
· For privileged/admin access, consider x.509 or an external identity provider (LDAP/Kerberos) where supported.
Validation
· Confirm security.authorization is enabled and unauthenticated operations are rejected.
· Review roles assigned to application accounts; validate they only have required actions on required DBs/collections.
Operational notes
· Create break-glass admin access with strong controls (MFA at the jump host, approvals, and tight audit).
Authorization
3.1 — Ensure least privilege for database accounts
Severity: Low
Automatable: Manual
Implementation
· Enable access control (authorization) and require authentication for all users and services.
· Use least-privilege roles: separate app users from admin users; avoid using built-in root for applications.
· Prefer SCRAM-SHA-256 for password auth; enforce strong password policy and rotation where feasible.
· For privileged/admin access, consider x.509 or an external identity provider (LDAP/Kerberos) where supported.
· Run mongod under a dedicated, non-privileged OS user and group.
· Harden the systemd unit: restrict capabilities, set file descriptor limits, and protect system directories.
· Restrict read/write access to data, config, and key files to the mongod service account only.
Validation
· Confirm security.authorization is enabled and unauthenticated operations are rejected.
· Review roles assigned to application accounts; validate they only have required actions on required DBs/collections.
· Check the running process user and filesystem permissions on data/config/key paths.
· Review systemd unit hardening settings (e.g., NoNewPrivileges, ProtectSystem, CapabilityBoundingSet).
Operational notes
· Create break-glass admin access with strong controls (MFA at the jump host, approvals, and tight audit).
3.2 — Ensure that role-based access control is enabled and configured appropriately
Severity: Critical
Automatable: Manual
Implementation
· Enable access control (authorization) and require authentication for all users and services.
· Use least-privilege roles: separate app users from admin users; avoid using built-in root for applications.
· Prefer SCRAM-SHA-256 for password auth; enforce strong password policy and rotation where feasible.
· For privileged/admin access, consider x.509 or an external identity provider (LDAP/Kerberos) where supported.
Validation
· Confirm security.authorization is enabled and unauthenticated operations are rejected.
· Review roles assigned to application accounts; validate they only have required actions on required DBs/collections.
Operational notes
· Create break-glass admin access with strong controls (MFA at the jump host, approvals, and tight audit).
3.3 — Ensure that MongoDB is run using a non-privileged, dedicated service account
Severity: Low
Automatable: Manual
Implementation
· Run mongod under a dedicated, non-privileged OS user and group.
· Harden the systemd unit: restrict capabilities, set file descriptor limits, and protect system directories.
· Restrict read/write access to data, config, and key files to the mongod service account only.
Validation
· Check the running process user and filesystem permissions on data/config/key paths.
· Review systemd unit hardening settings (e.g., NoNewPrivileges, ProtectSystem, CapabilityBoundingSet).
3.4 — Ensure that each role for each MongoDB database is needed and grants only the necessary privileges
Severity: High
Automatable: Manual
Implementation
· Enable access control (authorization) and require authentication for all users and services.
· Use least-privilege roles: separate app users from admin users; avoid using built-in root for applications.
· Prefer SCRAM-SHA-256 for password auth; enforce strong password policy and rotation where feasible.
· For privileged/admin access, consider x.509 or an external identity provider (LDAP/Kerberos) where supported.
· Run mongod under a dedicated, non-privileged OS user and group.
· Harden the systemd unit: restrict capabilities, set file descriptor limits, and protect system directories.
· Restrict read/write access to data, config, and key files to the mongod service account only.
Validation
· Confirm security.authorization is enabled and unauthenticated operations are rejected.
· Review roles assigned to application accounts; validate they only have required actions on required DBs/collections.
· Check the running process user and filesystem permissions on data/config/key paths.
· Review systemd unit hardening settings (e.g., NoNewPrivileges, ProtectSystem, CapabilityBoundingSet).
Operational notes
· Create break-glass admin access with strong controls (MFA at the jump host, approvals, and tight audit).
3.5 — Review Superuser/Admin Roles
Severity: High
Automatable: Manual
Implementation
· Enable access control (authorization) and require authentication for all users and services.
· Use least-privilege roles: separate app users from admin users; avoid using built-in root for applications.
· Prefer SCRAM-SHA-256 for password auth; enforce strong password policy and rotation where feasible.
· For privileged/admin access, consider x.509 or an external identity provider (LDAP/Kerberos) where supported.
Validation
· Confirm security.authorization is enabled and unauthenticated operations are rejected.
· Review roles assigned to application accounts; validate they only have required actions on required DBs/collections.
Operational notes
· Create break-glass admin access with strong controls (MFA at the jump host, approvals, and tight audit).
Data Encryption
4.1 — Ensure legacy TLS protocols are disabled
Severity: Critical
Automatable: Automated
Implementation
· Enable TLS for all client connections and intra-cluster traffic; disable plaintext listeners.
· Use CA-signed certificates (internal PKI is fine) and enforce modern protocols and ciphers.
· Store private keys with strict filesystem permissions; rotate certificates on a defined schedule.
Validation
· Confirm mongod.conf net.tls.mode is ‘requireTLS’ (or equivalent) and clients negotiate TLS.
· Test a plaintext connection attempt (should fail) and inspect logs for TLS handshake details.
Operational notes
· Plan certificate rotation for replica sets/shards to avoid quorum loss; roll nodes one at a time.
4.2 — Ensure Weak Protocols are Disabled
Severity: Low
Automatable: Automated
Implementation
· Apply the recommended configuration in mongod.conf and keep it under configuration management.
· Limit administrative access to dedicated jump hosts and privileged groups only.
· Document exceptions and track them in a risk register with a review date.
Validation
· Validate the setting using mongosh/config inspection and capture evidence (config snippet, command output).
Operational notes
· Treat any exception as time-bound; review at least quarterly or after major version upgrades.
4.3 — Ensure Encryption of Data in Transit TLS or SSL (Transport Encryption)
Severity: Critical
Automatable: Automated
Implementation
· Enable TLS for all client connections and intra-cluster traffic; disable plaintext listeners.
· Use CA-signed certificates (internal PKI is fine) and enforce modern protocols and ciphers.
· Store private keys with strict filesystem permissions; rotate certificates on a defined schedule.
Validation
· Confirm mongod.conf net.tls.mode is ‘requireTLS’ (or equivalent) and clients negotiate TLS.
· Test a plaintext connection attempt (should fail) and inspect logs for TLS handshake details.
Operational notes
· Plan certificate rotation for replica sets/shards to avoid quorum loss; roll nodes one at a time.
4.4 — Ensure Federal Information Processing Standard (FIPS) is enabled
Severity: Low
Automatable: Automated
Implementation
· Run mongod under a dedicated, non-privileged OS user and group.
· Harden the systemd unit: restrict capabilities, set file descriptor limits, and protect system directories.
· Restrict read/write access to data, config, and key files to the mongod service account only.
Validation
· Check the running process user and filesystem permissions on data/config/key paths.
· Review systemd unit hardening settings (e.g., NoNewPrivileges, ProtectSystem, CapabilityBoundingSet).
4.5 — Ensure Encryption of Data at Rest
Severity: Critical
Automatable: Manual
Implementation
· Apply the recommended configuration in mongod.conf and keep it under configuration management.
· Limit administrative access to dedicated jump hosts and privileged groups only.
· Document exceptions and track them in a risk register with a review date.
Validation
· Validate the setting using mongosh/config inspection and capture evidence (config snippet, command output).
Operational notes
· Treat any exception as time-bound; review at least quarterly or after major version upgrades.
File Permissions
7.1 — Ensure appropriate key file permissions are set
Severity: High
Automatable: Manual
Implementation
· Apply the recommended configuration in mongod.conf and keep it under configuration management.
· Limit administrative access to dedicated jump hosts and privileged groups only.
· Document exceptions and track them in a risk register with a review date.
Validation
· Validate the setting using mongosh/config inspection and capture evidence (config snippet, command output).
Operational notes
· Treat any exception as time-bound; review at least quarterly or after major version upgrades.
7.2 — Ensure appropriate database file permissions are set.
Severity: Low
Automatable: Manual
Implementation
· Apply the recommended configuration in mongod.conf and keep it under configuration management.
· Limit administrative access to dedicated jump hosts and privileged groups only.
· Document exceptions and track them in a risk register with a review date.
Validation
· Validate the setting using mongosh/config inspection and capture evidence (config snippet, command output).
Operational notes
· Treat any exception as time-bound; review at least quarterly or after major version upgrades.
Installation and Patching
1.1 — Ensure the appropriate MongoDB software version/patches are installed
Severity: Low
Automatable: Manual
Implementation
· Apply the recommended configuration in mongod.conf and keep it under configuration management.
· Limit administrative access to dedicated jump hosts and privileged groups only.
· Document exceptions and track them in a risk register with a review date.
Validation
· Validate the setting using mongosh/config inspection and capture evidence (config snippet, command output).
Operational notes
· Treat any exception as time-bound; review at least quarterly or after major version upgrades.
Operating System Hardening
6.1 — Ensure that MongoDB uses a non-default port
Severity: Low
Automatable: Automated
Implementation
· Apply the recommended configuration in mongod.conf and keep it under configuration management.
· Limit administrative access to dedicated jump hosts and privileged groups only.
· Document exceptions and track them in a risk register with a review date.
Validation
· Validate the setting using mongosh/config inspection and capture evidence (config snippet, command output).
Operational notes
· Treat any exception as time-bound; review at least quarterly or after major version upgrades.
6.2 — Ensure that operating system resource limits are set for MongoDB
Severity: Medium
Automatable: Manual
Implementation
· Apply the recommended configuration in mongod.conf and keep it under configuration management.
· Limit administrative access to dedicated jump hosts and privileged groups only.
· Document exceptions and track them in a risk register with a review date.
Validation
· Validate the setting using mongosh/config inspection and capture evidence (config snippet, command output).
Operational notes
· Treat any exception as time-bound; review at least quarterly or after major version upgrades.
6.3 — Ensure that server-side scripting is disabled if not needed
Severity: Low
Automatable: Manual
Implementation
· Apply the recommended configuration in mongod.conf and keep it under configuration management.
· Limit administrative access to dedicated jump hosts and privileged groups only.
· Document exceptions and track them in a risk register with a review date.
Validation
· Validate the setting using mongosh/config inspection and capture evidence (config snippet, command output).
Operational notes
· Treat any exception as time-bound; review at least quarterly or after major version upgrades.
Appendix A. Evidence collection tips
For each control, capture evidence that is easy to review and consistent run-to-run:
· Relevant mongod.conf excerpts (with sensitive values redacted).
· Command output from mongosh validations (read-only commands where possible).
· systemd unit overrides and file permission listings (ls -l) for key files.
· Network exposure evidence (ss -lntp, firewall rules, cloud security group exports).
· Log forwarding proof (sample events visible in SIEM) and retention configuration.
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