How to Secure MongoDB Instance

MongoDB is one of the most widely adopted NoSQL databases in modern application architectures, prized for its flexibility, scalability, and performance. However, its default configuration prioritizes ease of use over security, leaving many instances exposed to unauthorized access, data breaches, and cyberattacks. According to reports from security firms like Shodan and IBM, tens of thousands of MongoDB instances have been found publicly accessible on the internet without authentication — some containing sensitive data ranging from user credentials to financial records. Securing your MongoDB instance is not optional; it is a critical requirement for any production environment. This comprehensive guide walks you through the essential steps, best practices, tools, and real-world examples to ensure your MongoDB deployment is resilient against threats. Whether you’re managing a small application or a large-scale enterprise system, this tutorial provides actionable, technically accurate methods to lock down your database effectively.

Step-by-Step Guide

1. Disable BindIP to Restrict Network Access

By default, MongoDB binds to all network interfaces (0.0.0.0), making it accessible from any IP address on the internet. This is a major security risk. The first step in securing your MongoDB instance is to restrict network access to only trusted sources.

Open your MongoDB configuration file, typically located at:

• /etc/mongod.conf on Linux
• mongod.cfg on Windows (usually in C:\Program Files\MongoDB\Server\\bin\)

Locate the net section and modify the bindIp setting:

net:
port: 27017
bindIp: 127.0.0.1,192.168.1.10

In this example, MongoDB will only accept connections from the local machine (127.0.0.1) and a specific internal server (192.168.1.10). Avoid using 0.0.0.0 unless absolutely necessary and only in air-gapped networks.

After editing, restart the MongoDB service:

sudo systemctl restart mongod

Verify the change using:

netstat -tlnp | grep mongod

You should see MongoDB listening only on the specified IPs, not on all interfaces.

2. Enable Authentication and Create Administrative Users

Authentication is non-negotiable. MongoDB’s default behavior allows unrestricted access to databases. Enabling authentication forces clients to provide valid credentials before performing any operation.

First, connect to your MongoDB instance without authentication:

mongosh

Switch to the admin database and create a root user with administrative privileges:

use admin
db.createUser({
user: "admin",
pwd: "YourStrongPassword123!",
roles: [{ role: "root", db: "admin" }]
})

Next, enable authentication in the MongoDB configuration file. Add or update the security section:

security:
authorization: enabled

Restart MongoDB again to apply the change:

sudo systemctl restart mongod

Now, reconnect using credentials:

mongosh -u admin -p --authenticationDatabase admin

Always use strong, unique passwords and avoid common patterns. Consider using a password manager to generate and store credentials securely.

3. Create Role-Based Users for Applications

Never use the root user for application connections. Instead, create dedicated users with minimal required permissions using MongoDB’s role-based access control (RBAC).

For example, if your application only needs to read and write to a specific database called myapp, create a user with the readWrite role:

use myapp
db.createUser({
user: "appuser",
pwd: "AppPassword@456!",
roles: [{ role: "readWrite", db: "myapp" }]
})

For read-only access (e.g., reporting tools), use the read role:

use analytics
db.createUser({
user: "reportuser",
pwd: "ReportPass!789",
roles: [{ role: "read", db: "analytics" }]
})

For advanced use cases, create custom roles:

use admin
db.createRole({
role: "customDataViewer",
privileges: [
{ resource: { db: "myapp", collection: "" }, actions: ["find"] }
],
roles: []
})

Then assign this role to a user:

use myapp
db.createUser({
user: "viewer",
pwd: "ViewerPass!123",
roles: [{ role: "customDataViewer", db: "admin" }]
})

Always follow the principle of least privilege: grant only the permissions necessary for each user or service to function.

4. Enable Transport Layer Security (TLS/SSL)

Unencrypted network traffic between your application and MongoDB can be intercepted, leading to credential theft or data exposure. Enabling TLS/SSL encrypts all communication.

First, obtain a valid SSL/TLS certificate. You can use a certificate from a trusted Certificate Authority (CA) like Let’s Encrypt, or generate a self-signed certificate for internal use:

openssl req -newkey rsa:2048 -nodes -keyout key.pem -x509 -days 365 -out certificate.pem

Combine the key and certificate into a single file:

cat key.pem certificate.pem > mongodb.pem

Place the file in a secure directory, such as /etc/mongodb/ssl/, and set strict permissions:

sudo chmod 600 /etc/mongodb/ssl/mongodb.pem
sudo chown mongodb:mongodb /etc/mongodb/ssl/mongodb.pem

Update the MongoDB configuration file:

net:
port: 27017
bindIp: 127.0.0.1,192.168.1.10
tls:
mode: requireTLS
certificateKeyFile: /etc/mongodb/ssl/mongodb.pem
CAFile: /etc/mongodb/ssl/ca.pem  
Optional, if using CA-signed cert

Restart MongoDB and test the connection using mongosh with TLS:

mongosh --tls --host your-mongodb-server.com --port 27017 -u admin -p --authenticationDatabase admin

Verify TLS is active by checking the MongoDB logs for messages like “TLS/SSL is enabled.”

5. Configure Firewall Rules

Even with bindIp restrictions, a firewall adds an additional layer of defense. Use tools like ufw (Uncomplicated Firewall) on Ubuntu or firewalld on CentOS/RHEL.

On Ubuntu:

sudo ufw allow from 192.168.1.0/24 to any port 27017
sudo ufw deny 27017
sudo ufw enable

This allows connections only from the internal subnet (192.168.1.0/24) and blocks all others.

On CentOS/RHEL:

sudo firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="192.168.1.0/24" port protocol="tcp" port="27017" accept'
sudo firewall-cmd --permanent --remove-service=mongodb
sudo firewall-cmd --reload

Always test connectivity from allowed and denied IPs to confirm the rules are working. Use tools like nmap to scan your server from an external network and verify MongoDB is not exposed.

6. Disable Unused MongoDB Features

MongoDB includes several features that are unnecessary for most deployments and can be exploited if enabled. Disable them to reduce the attack surface.

Disable HTTP Interface

By default, MongoDB exposes a basic HTTP status interface on port 28017. This interface provides diagnostic information and can be used to gather system details. Disable it:

net:
port: 27017
http:
enabled: false

Disable REST Interface

The legacy REST interface (deprecated since MongoDB 3.6) should also be disabled. It is not enabled by default in modern versions, but verify it’s not active:

net:
port: 27017
rest:
enabled: false

Disable JavaScript Execution

JavaScript execution in queries (e.g., $where, db.eval()) can be used for code injection attacks. Disable it globally:

security:
authorization: enabled
javascriptEnabled: false

Applications should use native MongoDB queries instead of server-side JavaScript. This also improves performance and predictability.

7. Enable Audit Logging

Audit logging tracks all database operations, helping you detect unauthorized access or suspicious behavior. Enable it in the configuration file:

security:
authorization: enabled
auditLog:
destination: file
format: JSON
path: /var/log/mongodb/audit.log
filter: '{ "atype": { "$in": ["authenticate", "createUser", "dropUser", "updateUser", "grantRolesToUser", "revokeRolesFromUser"] } }'

The filter above logs only critical administrative actions. For comprehensive logging, remove the filter or use broader criteria.

Ensure the log directory exists and is writable by the MongoDB user:

sudo mkdir -p /var/log/mongodb
sudo chown mongodb:mongodb /var/log/mongodb

After restarting MongoDB, audit events will be recorded in the specified file. Use tools like jq to parse JSON logs:

jq '.atype' /var/log/mongodb/audit.log

Regularly review logs for anomalies such as failed authentication attempts, unexpected user creation, or privilege escalation.

8. Regularly Update MongoDB

Security vulnerabilities are discovered and patched regularly. Running outdated versions exposes you to known exploits.

Check your current version:

mongosh --eval "db.version()"

Compare it with the latest stable release on the official MongoDB downloads page.

On Ubuntu/Debian:

sudo apt update
sudo apt install mongodb-org

On RHEL/CentOS:

sudo yum update mongodb-org

Always test updates in a staging environment first. Follow MongoDB’s upgrade path documentation carefully — skipping versions may cause compatibility issues.

9. Backup and Encrypt Data at Rest

Even a secure database can be compromised through physical theft or misconfigured storage. Encrypt data at rest to protect against such scenarios.

MongoDB Enterprise Edition includes native encryption using the WiredTiger storage engine with AES-256 encryption. To enable it:

storage:
wiredTiger:
engineConfig:
configString: "encryption=(keyfile=/etc/mongodb/encryption-key.txt)"

Generate a secure key file:

openssl rand -base64 756 > /etc/mongodb/encryption-key.txt
sudo chmod 600 /etc/mongodb/encryption-key.txt
sudo chown mongodb:mongodb /etc/mongodb/encryption-key.txt

Restart MongoDB. All new data will be encrypted. Existing data remains unencrypted until migrated.

For MongoDB Community Edition, use full-disk encryption (e.g., LUKS on Linux or BitLocker on Windows). This protects the entire volume where MongoDB data files reside.

Additionally, implement automated, encrypted backups using mongodump and schedule them via cron:

0 2 * * * /usr/bin/mongodump --host localhost --port 27017 --username admin --password 'YourStrongPassword123!' --authenticationDatabase admin --out /backups/mongodb/$(date +\%Y-\%m-\%d)

Store backups offsite and encrypt them using GPG or similar tools before transfer.

10. Monitor and Alert on Suspicious Activity

Proactive monitoring is essential for detecting breaches early. Use MongoDB’s built-in metrics and integrate them with external monitoring tools.

Enable the serverStatus metrics endpoint:

db.serverStatus()

Monitor key metrics such as:

• Number of active connections
• Authentication failures
• Query latency spikes
• Memory and CPU usage

Integrate with tools like Prometheus and Grafana using the MongoDB Exporter:

docker run -d --name mongodb-exporter -p 9216:9216 -e MONGODB_URI="mongodb://admin:YourStrongPassword123!@localhost:27017" percona/mongodb_exporter

Set up alerts for:

• More than 5 failed login attempts in 5 minutes
• Unusual spike in database connections
• New user creation outside business hours

Use tools like Alertmanager, Datadog, or New Relic to send notifications via email, Slack, or PagerDuty.

Best Practices

Adopt the Principle of Least Privilege

Every user, service, and application should have the minimum set of permissions required to perform its function. Avoid granting roles like root or dbAdmin to application users. Use custom roles to define precise access levels. Regularly audit user permissions and revoke unused ones.

Use Strong, Rotated Passwords

Use passwords with at least 16 characters, including uppercase, lowercase, numbers, and symbols. Avoid dictionary words or patterns. Rotate passwords every 90 days and use a password manager to store them securely. Never hardcode credentials in application source code.

Isolate MongoDB in a Private Network

Never expose MongoDB directly to the public internet. Place it behind a firewall within a private subnet (VPC, private cloud, or internal LAN). Use a reverse proxy or API gateway to mediate application access. If remote access is required, use a secure tunnel (SSH, VPN, or WireGuard).

Implement Network Segmentation

Divide your infrastructure into zones: public, DMZ, application, and database. Only allow traffic from the application tier to the database tier. Block direct access from the internet or user devices to MongoDB.

Disable Unused Protocols and Ports

Turn off HTTP, REST, and diagnostic interfaces unless absolutely required. Close unused ports on the server. Use tools like nmap to scan your server and verify only necessary ports (e.g., 27017, 22) are open.

Regularly Review Logs and Audit Trails

Set up automated log rotation and retention policies. Review audit logs weekly for unauthorized changes. Correlate MongoDB logs with application and system logs to detect anomalies across layers.

Use Configuration Management Tools

Manage MongoDB configurations using infrastructure-as-code tools like Ansible, Puppet, or Terraform. This ensures consistency across environments and enables version control of security settings.

Train Developers and Operations Staff

Security is a team effort. Educate developers on secure coding practices, such as validating input, avoiding $where, and using connection strings with TLS. Train DevOps teams on secure deployment pipelines and incident response procedures.

Conduct Regular Security Audits

Perform quarterly penetration tests and vulnerability scans on your MongoDB instances. Use tools like Nessus, OpenVAS, or commercial services to identify misconfigurations. Engage third-party security experts for independent assessments.

Plan for Incident Response

Have a documented response plan for a compromised MongoDB instance. Steps should include: isolating the server, revoking all credentials, restoring from a clean backup, investigating the breach vector, and patching vulnerabilities. Practice this plan regularly.

Tools and Resources

Open Source Tools

• MongoDB Exporter – Exposes MongoDB metrics in Prometheus format for monitoring.
• Shodan – Search engine for internet-connected devices. Use it to scan for exposed MongoDB instances in your organization.
• Nmap – Network scanner to detect open ports and services. Use nmap -p 27017 --script mongodb-info <IP> to check for vulnerable instances.
• jq – Command-line JSON processor for parsing audit logs and serverStatus output.
• Fail2Ban – Automatically blocks IPs after repeated failed login attempts. Can be configured to monitor MongoDB authentication logs.

Commercial Tools

• Datadog – Comprehensive monitoring with MongoDB integrations, alerting, and dashboards.
• New Relic – Application performance monitoring with database-level insights.
• Percona Monitoring and Management (PMM) – Free, open-source platform for monitoring MongoDB and other databases.
• MongoDB Atlas – Managed MongoDB service with built-in security features like TLS, network isolation, and audit logging.

Documentation and Guides

• MongoDB Security Documentation – Official guide to authentication, authorization, and encryption.
• Configure SSL/TLS for MongoDB – Step-by-step TLS setup.
• CIS MongoDB Benchmarks – Industry-standard security configuration guidelines.
• NIST Cybersecurity Framework – Framework for managing cybersecurity risk.

Security Checklists

Use these as a quick reference:

• [ ] BindIP restricted to trusted IPs
• [ ] Authentication enabled
• [ ] Root user not used for applications
• [ ] TLS/SSL configured
• [ ] Firewall blocks public access
• [ ] HTTP/REST interfaces disabled
• [ ] JavaScript execution disabled
• [ ] Audit logging enabled
• [ ] MongoDB updated to latest stable version
• [ ] Data at rest encrypted
• [ ] Backups automated and encrypted
• [ ] Monitoring and alerting configured

Real Examples

Example 1: The 2017 MongoDB Breach Incident

In early 2017, over 30,000 MongoDB instances were found exposed on the internet without authentication. Attackers remotely deleted data and left ransom notes demanding Bitcoin payments. One company lost 10TB of customer data, including payment records and personal identifiers. The root cause? Default configuration with bindIp: 0.0.0.0 and no authentication enabled. The company had assumed their firewall would protect them, but the instance was exposed via a misconfigured cloud security group. After the breach, they implemented all steps outlined in this guide: network isolation, TLS, RBAC, audit logging, and automated backups. They also migrated to MongoDB Atlas for managed security.

Example 2: Healthcare Application with HIPAA Compliance

A healthcare SaaS provider storing patient records on MongoDB needed to comply with HIPAA regulations. They followed this security protocol:

• Deployed MongoDB in a private VPC with no public IP
• Enabled TLS 1.3 with a certificate from a trusted CA
• Created separate users: appuser (read/write), audituser (read-only), backupuser (backup roles)
• Enabled audit logging for all CRUD operations
• Used LUKS encryption on the underlying storage
• Automated daily encrypted backups to an S3 bucket with server-side encryption
• Integrated with Datadog for real-time alerts on login failures

They passed their HIPAA audit with zero findings. Their audit logs later helped trace a failed brute-force attempt from an internal IP, leading to the discovery of a compromised employee account.

Example 3: Startup Scaling Securely

A startup running MongoDB on a single VPS initially used default settings. As their user base grew, they noticed slow performance and occasional downtime. During a security review, they discovered:

• BindIP was 0.0.0.0
• No authentication enabled
• Port 27017 was open to the world
• They were running MongoDB 4.0 (outdated)

They implemented:

• Network restriction to their app server IP
• Strong password and RBAC for application user
• Upgraded to MongoDB 6.0
• Enabled TLS using Let’s Encrypt
• Set up Fail2Ban to block repeated login attempts

Within 24 hours of deployment, they saw a 90% drop in failed login attempts from bots. Their application performance improved due to reduced network noise. They later migrated to a managed cluster for scalability and automated patching.

FAQs

Can I use MongoDB without authentication?

No, you should never use MongoDB without authentication in production. Even in development, it’s best practice to enable it to avoid accidental exposure. Default configurations are insecure by design.

Is MongoDB Atlas more secure than self-hosted MongoDB?

Yes, MongoDB Atlas provides enterprise-grade security out of the box: automatic TLS, network peering, IP whitelisting, audit logging, and automatic patching. It’s recommended for most users who don’t require full control over infrastructure.

How often should I rotate MongoDB passwords?

Rotate passwords every 60–90 days. Use automated tools to rotate credentials in your applications without downtime. Consider using secrets management systems like HashiCorp Vault or AWS Secrets Manager.

What’s the difference between “readWrite” and “readWriteAnyDatabase”?

readWrite grants access only to the specified database. readWriteAnyDatabase grants write access to all databases on the server — a high-risk privilege. Avoid using readWriteAnyDatabase unless absolutely necessary.

Can I use MongoDB with a cloud provider’s firewall?

Yes, but don’t rely on it alone. Use cloud firewalls (e.g., AWS Security Groups, Azure NSGs) in combination with MongoDB’s bindIp and internal firewall rules. Layered security is essential.

What happens if I lose my MongoDB admin password?

If you lose access and have no other admin user, you can restart MongoDB in bypass mode:

1. Stop the MongoDB service
2. Start it with mongod --bind_ip 127.0.0.1 --port 27017 --noauth
3. Connect with mongosh and create a new admin user
4. Stop MongoDB and restart normally with authentication enabled

Always maintain at least two admin users in different locations.

Does MongoDB encrypt data by default?

No. Data at rest is unencrypted in MongoDB Community Edition unless you enable WiredTiger encryption (Enterprise) or use full-disk encryption. Always encrypt sensitive data.

How do I test if my MongoDB is secure?

Use Shodan.io to search for your server’s public IP. If MongoDB appears with “no auth” or “open access,” it’s exposed. Run an Nmap scan: nmap -p 27017 --script mongodb-info <IP>. If it returns version and database info without authentication, your instance is vulnerable.

Conclusion

Securing a MongoDB instance is not a one-time task — it’s an ongoing discipline that requires vigilance, configuration discipline, and continuous monitoring. The default settings of MongoDB are designed for developer convenience, not production security. Leaving your database exposed or unauthenticated is equivalent to leaving your front door unlocked in a high-crime neighborhood. By following the steps outlined in this guide — restricting network access, enabling authentication, enforcing TLS, applying least privilege, enabling audit logs, and maintaining updates — you significantly reduce the risk of data breaches, compliance violations, and operational disruption.

Remember: security is not a feature — it’s a culture. Integrate these practices into your development lifecycle, automate configuration enforcement, and train your team to prioritize security at every stage. Whether you’re managing a small prototype or a global enterprise system, the principles remain the same. A secure MongoDB instance is not just a technical requirement — it’s a trust signal to your users, stakeholders, and regulators. Implement these measures today, and sleep easier knowing your data is protected.