SSH in IoT: Protecting Smart Devices from Cyber Threats

The Internet of Things (IoT) market is rapidly expanding in today’s modern interconnected world. From smart homes and security cameras to medical devices and industrial sensors, make everyone’s life easier and more efficient. But along with their convenience, they often operate with fewer security measurements. Cyberattackers leverage poorly protected IoT devices, like devices with default credentials, limited encryption, and obsolete firmware—making them easy to leverage. Studies highlight that in 2024, IoT breaches will increase by 27%—hackers leverage compromised devices to launch cyberattacks at a broader level. So how to protect IoT devices from cyberattacks?

The Secure Shell (SSH) protocol emerges as a pristine solution for establishing secure connections, allowing users to remotely manage IoT devices. This guide will break down the concept of SSH and how it helps with IoT security in a simple and easy-to-understand way.

What Makes IoT Devices So Vulnerable?

In contrast to traditional computers, modern IoT devices are often designed with weaker security measures, making them more vulnerable to cyber threats. Here are some reasons why these devices are a primary target for hackers:

1. Insecure Default Passwords: Many IoT devices come with default configurations or factory-set passwords like “12345” or “admin,” which makes it easy for hackers to guess. 
   
   

2. Lack of encryption: Some IoT devices do not encrypt their data before sending—this allows hackers to intercept credentials and sensitive information over the network easily.
   
   

3. Use insecure components and software: Many IoT devices use susceptible or outdated software or components of IoT, making it easy for hackers to take advantage of vulnerabilities. 
   
   

4. Lack of updates: Many devices are unmanaged, which means the manufacturers rarely release security updates or patches—resultant devices are vulnerable to exploits. 

Without proper security and encryption, the smart IoT devices are vulnerable for hackers. That’s why strong security measures and communication protocols are required to protect your IoT devices and sensitive information from cyber threats.

What is the SSH?

The SSH (secure shell) is a protocol or method to securely access IoT devices remotely over an unsecured network. Instead of sending data in plain text, SSH uses encryption methods like cryptography to secure communication between devices. Think of SSH as an encrypted tunnel between you and your IoT devices—allows server administrators to remotely manage devices. Whether you need to log in to your devices afar to troubleshoot an issue or keep an eye on your device’s performance, SSH ensures the security of your devices. SSH is more secure than other alternatives like Rlogin or Telnet, and it is commonly used for transferring files and managing the infrastructure.

How does SSH protect the IoT devices?

Encrypted Communication: SSH establishes a strong, secure connection between the IoT device and the source device where the data needs to be transmitted. This prevents hackers from snooping on transmitted data—instead of sensitive information, they will get garbage data that cannot be decrypted.

Restrict Unauthorized Access: SSH uses authentication techniques instead of using weak passwords, like public key cryptography. This allows both the client and severs to verify each other’s identity using SSH keys—public and private keys. 

Minimises the Attack Risks: Unlike other insecure IoT protocols like Telnet, which sends data in plain text—SSH uses encryption methods to transmit the data. 

Secure Remote Device Management: SSH allows users and administrators to access and monitor IoT devices remotely—protecting them from cyber threats. This technique is used for simplifying various tasks like transferring files, updating or configuring settings, and installing software from a distance.

Meanwhile, the SSH protocol is among the most fascinating ways to safeguard IoT devices from cyber threats. Implementing this method in securing your devices requires careful and strategic tactics—you may need to learn how to implement SSH in IoT devices.

How to Secure IoT Devices with SSH?

As mentioned above SSH is crucial for securing IoT devices—-Let’s learn how to implement it properly.

1. Use SSH Keys Authentication Instead of Passwords: 

One of the most concerning causes of cyberattacks is weak passwords—the default or easy passwords can easily be guessed by hackers. Instead of using weak passwords for each server, use SSH keys for enhancing security and authentication once per session. SSH keys are the pair of public and private keys that help you secure your devices effectively instead of relying on passwords.

Steps to Set up SSH Key Authentication:

• Generate an SSH Key pair on Your Local Machine

ssh-keygen -t rsa -b 4096

• Copy the Public Key to Your Server

ssh-copy-id user@device

• Disable Password Authentication (in SSH configuration file /etc/ssh/sshd_config)

PasswordAuthentication no

Now those devices that have the correct private key can only connect with your IoT devices—making it impossible to intercept.

2.Change the Default SSH Port

What is an SSH port? SSH runs on the default port 22 on a Linux server, where hackers block access on the server when trying to access the system. To safeguard your device from exploit, change the SSH port—this makes it impossible for hackers to attack.

Steps to change the SSH port:

• Access the SSH configuration file using a text editor

sudo nano /etc/ssh/sshd_config

• Change the port settings with a non-standard number

Port 45654

• Restart the SSH service to apply the changes

sudo systemctl restart ssh

• Test the New Port

ssh -p 45654 user@your_server_ip.

3.Restrict SSH Access with Firewalls

Set the limit on who can access your IoT devices—restrict SSH access so only encrypted and trusted devices can connect. Integrate firewall regulations with SSH that allow only specific IP addresses to connect while blocking others.

Here is how restricting SSH access with a firewall (UFW)

ufw allow from 192.168.1.100 to any port 45219

ufw enable

This will enable the security of the devices—only specific and secure devices can access the SSH services.

4.Keep SSH configuration and Device Updated

Regularly, manage and update the configuration file and system packages to enhance the security and authentication. If your software or firmware are outdated, no security measure is effective—staying up to date is important.

Best practices to keep the system updated:

• Check the firmware and software updates at least once a month. 
• Keep an eye on SSH logs for suspicious activity:

cat /var/log/auth.log

• Disable root login (sshd_config settings):

PermitRootLogin no

Final Thoughts

As IoT devices are becoming increasingly essential across diverse industries, implementing strong security measures is not just an afterthought. The weak and insecure devices are highly vulnerable to exploit, and cybercriminals are always looking for these vulnerabilities. Those organisations that implement this SSH authentication, restrict access, and keep devices up-to-date will significantly reduce the risk of attacks. By implementing these steps—encyption, remote IoT device management, and authentication—you can protect your IoT devices from cyberthreats in this modern digital era. If you are worried about the security of the devices connected to the internet, it is the right time to take action. Try implementing the SSH protocol today!