How to Secure Your Router Against Mirai Botnet Attacks

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Hey there! With Mirai botnet attacks on the rise, now is the time to secure your router. As your new tech-savvy friend, I‘ve put together this comprehensive guide so you can protect your home network. Let‘s dive in!

What Makes Mirai So Dangerous

Before we start fortifying your router, you should understand what makes Mirai such a tricky threat. Mirai is malware that targets the Internet of Things – all those smart devices in your home like cameras, thermostats, and lights.

Diagram of IoT devices in a home

Image credit: Brad Neathery on Unsplash

By 2020, there were over 15 billion IoT devices worldwide. That‘s a lot of potential victims! Once infected with Mirai, these devices get corralled into something called a botnet. All the compromised gadgets work together to overwhelm websites and online services with junk traffic.

Just a couple infected cameras or appliances can generate enough firepower to take down huge sites! According to Cloudflare, the average Mirai-powered botnet consists of around 80,000 enslaved devices. One particularly nasty Mirai variant called Satori had over 500,000 bots under its control.

And your router plays a crucial role in this. Mirai uses your router as an entry point to take over all the IoT gadgets in your home network. That‘s why securing your router should be your top priority.

Recognizing Symptoms of Infection

How do you know if your router‘s already been compromised by Mirai or a similar IoT botnet? Here are the common warning signs I told you to keep an eye out for:

  • Your internet service seems to run slower, with more lag and buffering issues. This could indicate your router is occupied attacking others!

  • You notice unusual spikes in network traffic and bandwidth usage. Botnets generate large volumes of junk data.

  • Your router‘s web dashboard shows unfamiliar login accounts or remote IP addresses.

  • Admin password no longer works and you‘re locked out of the router controls.

  • Certain websites won‘t load – a sign of corrupted DNS settings.

According to F-Secure labs, a worrying 82% of routers they tested contained some sort of vulnerability. My advice? Don‘t take any chances – assume the worst and proceed with securing your router!

Start With Strong Passwords

Let‘s get right into the good stuff! The first step is using better router passwords so Mirai can‘t easily break in. Most routers still come preset with weak default logins like ‘admin/admin‘ or ‘password‘. These are practically an invitation for hackers!

Instead, your Wi-Fi network and router admin account should have passwords with at least 15 random characters – something like ‘Zo3@YwQ%XBvt77#‘ (but don‘t use that exact one!) Make sure to use a mix of letters, numbers and symbols too.

I know passwords like these are a pain, but password managers like LastPass and 1Password make them easy to handle. Be sure to change the SSID network name from the default too.

Oh, and this should go without saying, but avoid using personal info like your birthday or pet‘s name. Hackers can easily find that through social media and public records. Stick to total gibberish for passwords and you‘ll be way more secure.

Update Firmware Regularly

Another essential router security step is always installing the latest firmware updates. Router vendors like Netgear, TP-Link and D-Link periodically release patches to fix bugs and close security holes.

Mirai looks for known firmware vulnerabilities to exploit, so staying on top of updates really frustrates these attacks. Most routers have an auto-update or one-click upgrade feature, so there‘s no excuse to fall behind!

I recommend checking your router vendor‘s support site for new firmware once a month and installing any available updates. This locks the doors against new Mirai malware variations.

Harden Your Router‘s Configuration

A well-configured router acts as a shield against malicious traffic entering your home network. Here are some smart tweaks I recommend making:

Disable remote admin access – Shut down remote protocols like SSH or Telnet that Mirai uses to infiltrate your router. Only allow admin access from your home‘s IP range if needed.

Turn off side services – Most people don‘t use their router as a media server or IoT hub. Disable UPnP, Plex, AI features and any other unnecessary extras.

Set up firewall rules – Configure your router to block traffic from risky countries like China, Russia and Romania. This stops phishing and brute force attacks.

Use encryption – Enable WPA3 Wi-Fi encryption if your router supports it, the latest standard for stopping snooping. Also use a VPN for all device connections.

Isolate your IoT devices – Put smart home gadgets on a separate network segment so malware can‘t jump to PCs and phones.

Customize DNS – Use or instead of your ISP‘s DNS which could be compromised. This prevents access blocking.

Regularly monitor the dashboard – Check connected devices and traffic rules for anything fishy. Catch issues fast.

Advanced Options for Paranoid Protection

For super rigorous router lockdown, you can take things up a notch with some extra precautions:

Open source router firmware – Flash something like DD-WRT or OpenWrt instead of standard firmware for more configurability.

A dedicated firewall – An advanced firewall like pfSense adds powerful network monitoring and malware blocking.

A business-class router – More expensive but commercial routers have better security capabilities and support.

Router hardening scripts – Terminal scripts like Lynis perform expert-level router security configuration automatically.

DNS filtering – Services like OpenDNS, Quad9 or NextDNS filter out known malicious domains and botnet connections.

Deep packet inspection – DPI analyzes your network traffic for signs of malware communication. Available on some routers or through standalone hardware.

For most people, just sticking to strong passwords, prompt updates and smart settings is sufficient. But experts can take it up a level with open source firmware, pro-grade routers and other hardcore techniques!

Recovering From Infection

Think your router‘s been hijacked by Mirai or another IoT botnet? Getting clean requires fully resetting to factory conditions:

  1. Immediately unplug the router to isolate it from the network.

  2. Set up a separate clean spare router in the meantime so your internet stays online.

  3. Perform a total factory reset on the infected router to wipe all settings and malware.

  4. Flash the latest official firmware, even if supposedly already up-to-date.

  5. Configure the router from scratch with new passwords, disabled remote access and custom DNS.

  6. Use malware tools like F-Secure to scan firmware for leftover infections.

  7. Monitor traffic closely over the next few weeks for suspicious patterns.

If issues persist even after a reset, you may need to install completely fresh third-party firmware like Tomato or DD-WRT to fully flush out malware.

We‘ve Got This!

Phew, we covered a ton of ground! The Mirai botnet remains a tricky beast, but I‘m confident all these security tips will help keep your home network protected. My advice boils down to:

  • Use long, complex passwords
  • Regularly update firmware
  • Harden router configurations
  • Isolate and monitor IoT devices
  • Reset completely if infected

And don‘t get complacent! This threat is constantly evolving. But now you know how to spot botnet warning signs and have the right techniques to fight back. Together, we can send Mirai packing! Feel free to reach out if any other router security questions come up. Talk soon!


Written by Alexis Kestler

A female web designer and programmer - Now is a 36-year IT professional with over 15 years of experience living in NorCal. I enjoy keeping my feet wet in the world of technology through reading, working, and researching topics that pique my interest.