Don‘t Let the Mirai Botnet Attack Your Network! Here‘s How to Protect Your Router

Have you heard about the Mirai botnet that has hijacked millions of routers and cameras? This rapidly evolving threat targets insecure internet of things (IoT) devices—and then uses them to launch crippling cyberattacks.

By leveraging devices with weak passwords and unpatched flaws, these zombie botnets can take down entire websites and internet infrastructure. The Dyn attack of 2016 showed how destructive Mirai can be when fully unleashed.

So how exactly does Mirai break in, and how can you stop it from incorporating your router or IoT gear into the botnet army? I‘ll answer these questions in detail below. But first, let‘s examine why the Mirai epidemic requires urgent security action.

The Growing Scale of the Mirai Botnet Menace

Mirai and its many variants now power some of the world‘s largest distributed denial of service (DDoS) botnets. The original Mirai first appeared in 2016, but the publicly released source code opened the floodgates for new malicious modifications.

According to security researchers, Mirai botnets now spread at a rate of nearly 100,000 new infected devices per month. Estimates suggest over 5 million total devices have been compromised to date. Home consumer routers and internet-connected cameras make up over 90% of infected victims.

But Mirai continues to expand its horizons. New strains now target Linux-based smart retail displays, medical imaging equipment, industrial control systems and more. No internet-enabled device is safe from potential incorporation into these sprawling bot armies.

And as bot herders assemble larger networks of compromised devices, the scale of attacks continues to grow. Recent Mirai attacks include:

  • A 8.5tbps DDoS barrage targeting Cloudflare infrastructure in 2020 – The most powerful attack observed to date
  • Terabit floods on Liberian telecoms bandwidth in 2021 – Causing nationwide connectivity outages
  • Ongoing bombardment of Lithuanian government sites – Believed to be affiliated with state-sponsored hackers

These distributed assaults harness massive device swarms—often amplified by reflected traffic—to crush targets and obstruct the routing infrastructure itself.

With new strains emerging regularly and rising economic incentives for DDoS-for-hire, Mirai is unlikely to dissipate anytime soon. That‘s what makes router and IoT security so critical right now.

Identifying a Possible Mirai Infection

Detecting router compromise can be tricky since Mirai actively evades detection. After breaking in using default credentials on Telnet ports, the malware disguises its presence.

However, there may be subtle signs of infection:

  • Internet connectivity issues, such as lag, buffering or brief outages
  • Unusually high bandwidth usage indicating DDoS participation
  • New unfamiliar devices appearing on your network
  • Login attempts or configuration changes not made by you
  • Router rebooting or operating unstable

Seeing any of these issues should heighten suspicion. Scan router logs for unfamiliar inbound connections. You may also spot unusual outbound traffic in Mirai‘s attempts to spread.

Tools like Wireshark and nmap provide packet-level network visibility that can reveal malware command and control traffic. Intrusion detection systems also help identify Mirai and other IoT botnet patterns.

But lacking strong router safeguards in the first place leads to the highest probability of compromise.

Locking Down Your Home Router Against Attack

Hardening your router against breach attempts is the most critical first line of defense. Here are 8 essential security steps I recommend:

1. Change the Default Password

The default admin login credentials are utterly useless for protecting against Mirai. Set a strong password at least 15 characters in length containing numbers, capital letters, symbols and non-dictionary terms.

2. Disable Remote Web Admin Access

Restrict the admin console exclusively to your local network instead of exposing it on the public WAN port. Verify remote management ports are disabled or protected by VPN.

3. Turn Off Unused Services Like Telnet

Mirai targets ports like 23 for Telnet remote command access. Cut off this attack vector by disabling deprecated Telnet along with FTP, SSH, UPnP and any other non-essential services.

4. Install Critical Firmware & Security Updates

Patch new vulnerabilities immediately to prevent zero-days from being used in conjunction with default password attacks. Keep firmware 100% up to date.

5. Enable Your Router Firewall

Basic stateful inspection filtering can help block inbound scans and malware command traffic. Restrict device internet access to only essential outside communication.

6. Use Strong Wi-Fi Encryption

Make sure your wireless network uses modern WPA2 or WPA3 encryption with a random password. Avoid obsolete WEP flaws which lead to deeper network penetration.

7. Isolate IoT Devices on Separate Networks

Your IP camera shouldn‘t have access to servers and PCs. Segment smart appliances onto IoT VLANs or guest Wi-Fi with restricted rights. This also prevents lateral movement if any become infected.

8. Monitor Traffic for Anomalies

Watch router logs for unusual connections and HTTP requests. Set bandwidth usage alerts and check for odd traffic spikes indicative of bot activity. Investigate anything suspicious.

But even with routers fully locked down, threats remain for innocent IoT devices on local networks. Let‘s examine these next.

Five Must-Do Security Steps for IoT Gear

Smart home gadgets like DVR security cameras still run Linux and feature the very flaws Mirai exploits. Here‘s how to get them secure:

  • Replace default credentials – Set device passwords over 15 characters using special characters and non-dictionary terms.
  • Disable Telnet and SSH – Only use them if absolutely required and even then limit access to your trusted admin IP address range only.
  • Turn off UPnP – Prevent Unauthorized external access requests from succeeding.
  • Install available firmware updates – Patch vulnerabilities through latest device firmware releases. Sign up for vendor notifications.
  • Connect devices to an IoT VLAN – Isolate cameras, smart speakers and similar devices into their own network segment with limited rights.

My ideal set up places all such IoT equipment behind an isolated firewall to enforce strict traffic rules. You can allow only required HTTPS web access out to the internet and block everything else externally.

This makes infiltration much harder in case any device passwords get cracked later on. Monitoring internal traffic ensures quick detection as well.

Advanced Traffic Inspection Takes Detection Further

While the above measures minimize infection risk, I also recommend implementing intrusion detection systems to identify malicious traffic.

IDS solutions use traffic pattern analysis and botnet-specific signatures to uncover:

  • Active malware command & control communications
  • Initial inbound scans and brute force login attempts
  • Unusual outbound connection requests

And by continuously inspecting traffic for anomalies, they serve as an early warning system.

Advanced malware protection platforms take this to the next step with sandbox environments to reveal actual device exploit and infection attempts. They block detected threats in real time before damage can occur.

The Ongoing Evolution Demands Constant Vigilance

If anything is clear amidst the Mirai chaos, it‘s that IoT botnets continue to adapt rapidly. New variants emerge regularly exploiting fresh vulnerabilities and spreading new ways.

So while solid password hygiene and network monitoring practices provide strong foundations, we must go further. Continuously scanning device firmware versions against known threats can uncover emerging risks before they fully Weaponize.

This means expanding vulnerability management programs to include often neglected smart home gear alongside servers and computers. It requires constantly tracking threat reports and intelligence from your information security vendors and partners.

And maintaining comprehensive device inventories allows promptly identifying those requiring priority patches and segmented isolation.

With hundreds of new IoT device types launching annually, we need such proactive stances to prevent home networks from being assimilated into these bot armies.

The Mirai saga offers sobering lessons around extending holistic cyber risk management to ALL internet-connected equipment. I hope the comprehensive guidance above helps significantly boost your resilience.

Please share your feedback or questions in the comments below!