DNS Server Security: Passwords at Risk?

TL;DR

A rogue DNS server can see your passwords if you’re using unencrypted connections to websites. However, modern security measures like HTTPS and DNS over TLS/HTTPS significantly reduce this risk. Regularly check your DNS settings and use a reputable DNS provider.

Understanding the Risk

DNS (Domain Name System) translates website names (like google.com) into IP addresses (like 142.250.185.142). When you type a web address, your computer asks a DNS server to find that IP address. Traditionally, this communication wasn’t encrypted.

How a Rogue DNS Server Can See Your Data

1. Unencrypted Queries: If you use an unencrypted DNS connection (the default in many older setups), the request for the website’s IP address is sent in plain text.
2. Website Requests: Once your computer has the IP address, it sends a request to that website. If the website doesn’t use HTTPS, the data you send (including usernames and passwords) can also be intercepted by someone monitoring the network.
3. DNS Server Logs: A rogue DNS server can log the websites you visit, potentially revealing sensitive information if those sites aren’t secure.

Steps to Protect Yourself

1. Use HTTPS Everywhere: Always look for “https://” at the beginning of a website address and a padlock icon in your browser’s address bar. This encrypts the communication between your computer and the website, protecting your data even if the DNS server is compromised.
2. Enable DNS over TLS (DoT) or DNS over HTTPS (DoH): These protocols encrypt your DNS queries, preventing eavesdropping.
   • Windows:

     netsh interface ip set dns name-server 8.8.8.8 primary

     (This example uses Google’s public DNS server; replace with a provider supporting DoT/DoH.) You may need to configure the specific DoT/DoH settings in your network adapter properties (Advanced TCP/IP Settings -> DNS tab).

   • macOS: System Preferences > Network > Select your connection > Advanced > DNS. Add a DNS server that supports DoT/DoH (e.g., Cloudflare 1.1.1.1 or Google 8.8.8.8) and configure the protocol in Terminal using `scutil –dns` commands (more complex, see provider documentation).
   • Browsers: Most modern browsers (Chrome, Firefox, Edge) have built-in options to use DoH. Check your browser settings under Privacy & Security.
     • Firefox: Options > General > Network Settings > Enable DNS over HTTPS
     • Chrome/Edge: Settings > Security and privacy > Use secure DNS
3. Choose a Reputable DNS Provider: Select a well-known and trusted DNS provider like Cloudflare (1.1.1.1), Google Public DNS (8.8.8.8, 8.8.4.4), or Quad9 (9.9.9.9). These providers typically have strong security measures.
4. Check Your Router Settings: Your router likely has DNS settings. Ensure these are configured to use a secure provider and that no rogue DNS servers are listed.
   • Access your router’s admin interface (usually via a web browser – check your router’s manual for the address, often 192.168.1.1 or 192.168.0.1).
   • Look for DNS settings under WAN/Internet configuration.
5. Regularly Scan Your Network: Use a network scanner to identify any unexpected devices or servers on your network.

What about VPNs?

A Virtual Private Network (VPN) encrypts all of your internet traffic, including DNS queries. This adds an extra layer of security and can protect you from rogue DNS servers and other eavesdroppers.