Murmur (Mumble) Server Security Risks

TL;DR

Connecting to a Murmur server can be risky if not done carefully. The main concerns are denial-of-service attacks, account compromise due to weak passwords, and potential eavesdropping if encryption isn’t properly configured. This guide explains how to minimise those risks.

Murmur (Mumble) Server Security Risks & Solutions

1. Understand the Risks
• Denial-of-Service (DoS) Attacks: Murmur servers can be targeted with attacks that flood them with requests, making them unavailable.
• Account Compromise: Weak passwords on server accounts or client connections make it easy for attackers to gain access.
• Eavesdropping/Man-in-the-Middle (MitM) Attacks: Without proper encryption, your voice and text chat can be intercepted.
• Server Software Vulnerabilities: Older versions of Murmur may have known security flaws.
2. Keep Your Server Software Updated

This is the most important step! Updates often include critical security patches.

• Check for updates regularly on the Mumble website or through your package manager (if you installed Murmur that way).
• Example using apt (Debian/Ubuntu):

sudo apt update

sudo apt upgrade mumble-server

3. Configure Strong Encryption
• Ensure your Murmur server is configured to use TLS (Transport Layer Security) for encrypted connections. This protects voice and text chat from eavesdropping.
• Check your murmur.ini file for the following settings:

ssl = true

ssl_cert = /path/to/your/server.pem

ssl_key = /path/to/your/server.key

• Generate a self-signed certificate (for testing) or obtain one from a Certificate Authority (CA) for production use. Using Let’s Encrypt is a good free option.
4. Use Strong Passwords
• For all server accounts, choose strong, unique passwords that are at least 12 characters long and include a mix of uppercase letters, lowercase letters, numbers, and symbols.
• Encourage users to do the same for their client connections.
• Consider using a password manager.
5. Restrict Server Access
• Firewall: Configure your firewall (e.g., ufw on Linux) to only allow connections to the Murmur server port (default is 6432 for UDP and TCP).

sudo ufw allow 6432/udp comment 'Murmur UDP'

sudo ufw allow 6432/tcp comment 'Murmur TCP'

• Bind Address: If you only want the server accessible from your local network, bind it to a specific IP address instead of all interfaces (0.0.0.0).
6. Limit User Permissions
• Assign users only the permissions they need. Avoid giving everyone admin access.
• Murmur has different permission levels; understand what each one allows before assigning it.
7. Monitor Server Logs

Regularly review your Murmur server logs for suspicious activity, such as failed login attempts or unexpected errors.

• Log files are typically located in the Murmur server’s data directory.
8. Consider a Dedicated Server

If you’re running a public Murmur server, consider using a dedicated virtual private server (VPS) or cloud instance to isolate it from other services on your network.