Here's the thing about IoT security: it's a mess. And it's getting messier.
Every smart thermostat, IP camera, and industrial sensor you connect to your network is another potential way in for attackers. We're not talking about sophisticated nation-state hackers here (though they're interested too). We're talking about automated bots scanning the internet of things for devices still using "admin/admin" as login credentials.
IoT security protects your connected devices, IoT systems, and networks from cyber threats, unauthorized access, and the vulnerabilities that come with internet-connected hardware. This guide covers the real IoT security challenges you're facing, practical security best practices that actually work, and how to secure IoT devices without losing your mind.
The attack surface keeps expanding. Every networked device is a potential entry point, and unlike your laptops and servers, most IoT devices have zero security built in.
Different industries, different nightmares: Healthcare organizations worry about ransomware locking up medical devices and wearables. Manufacturing plants can't afford automation systems going offline. Smart home users don't realize their baby monitor might be streaming to strangers. These aren't hypothetical scenarios, they're happening right now.
IT meets OT, chaos ensues: When operational technology (OT) and traditional IT security collide, things get complicated fast. You've got industrial protocols that were never designed for internet connectivity suddenly exposed to cyber threats. The network security measures that work for your office might break your production line.
Real-time threat detection isn't optional anymore. By the time you notice something's wrong, cyberattacks have already moved laterally through your network.
Let's talk about what's actually breaking.
Default passwords are still everywhere. I know, I know, we've been screaming about this for years. But manufacturers keep shipping devices with "admin/password" baked in, and users keep not changing them. The Mirai botnet proved how devastating this is back in 2016, infecting hundreds of thousands of smart devices and launching DDoS attacks (distributed denial of service) that took down major websites. The scary part? Mirai's source code is public now, so anyone can run their own IoT botnet.
Nobody's updating firmware. Most IoT devices never get security updates. Ever. Manufacturers abandon older models, leaving known vulnerabilities unpatched forever. Even when updates exist, who's got time to manually patch thousands of sensors?
Endpoint security? What endpoint security? IoT devices run stripped-down operating systems with barely enough memory to function. Forget about installing antivirus or implementing strong authentication, there's literally no room for it.
Malware, ransomware, and botnet recruitment: Once attackers compromise one device, they use it as a foothold. Malware spreads across your IoT network. Ransomware encrypts critical systems. Botnet operators turn your devices into attack weapons.
Physical tampering and supply chain risks: Many IoT devices sit in unlocked closets or outdoor locations. An attacker with physical access can extract credentials or modify firmware. Worse, supply chain compromises happen before you even unbox the device, with attackers injecting malware during manufacturing or shipping.
Here's what works in the real world.
Segment your network, seriously, do this first. Put IoT devices on separate VLANs, isolated from your core network. This is hands-down the most effective security measure you can implement. When (not if) a device gets compromised, segmentation stops attackers from reaching your critical systems. Treat IoT like you'd treat guest wifi, assume it's hostile.
Kill those default passwords. Every. Single. Device. Use unique, complex credentials. Enable multi-factor authentication if the device supports it. For higher-security environments, use certificate-based authentication instead of passwords.
Go zero-trust. Don't trust any device by default. Zero-trust security means continuous verification, every device proves its identity every time it tries to access something. This works great for IoT networks because device behavior should be predictable.
Encrypt everything with TLS. Data moving between internet-connected devices and your backend systems needs encryption. TLS (Transport Layer Security) protects sensitive data from interception.
Lock down your routers and wi-fi. Change router default credentials, disable unnecessary services, enable WPA3 encryption, update firmware regularly. Create a separate wi-fi network just for IoT devices.
Limit what each device can do. If your smart thermostat only needs to talk to your HVAC system and one cloud service, block everything else. Function-based access control limits damage when devices get compromised.
You can't protect what you can't see. And most organizations have no idea what IoT devices are actually on their networks.
This is where monitoring becomes critical. You need tools that can discover and inventory all devices on your network, including the shadow IT stuff nobody told you about.
PRTG Network Monitor handles this automatically. It discovers IoT devices across your network, monitors their behavior in real time, and alerts you when something looks wrong. A smart camera suddenly scanning your network? A sensor transmitting gigabytes of data? PRTG catches it.
The platform supports both IT and OT environments, with built-in sensors for industrial protocols like Modbus, OPC UA, and MQTT. Whether you're monitoring office IoT devices or industrial automation systems, PRTG gives you unified visibility.
What you get with PRTG:
Learn more about IoT and OT monitoring with PRTG or start a free 30-day trial to see how it works in your environment.
Enterprise: Zero-trust architecture, strict segmentation, comprehensive monitoring. Integrate with your existing cybersecurity framework. Stay compliant with IoT security regulations and standards.
Smart home: Separate network for IoT devices, router security, selective device purchasing. Research vendor security practices before buying.
Healthcare: Patient safety first. Strict access control for medical devices, compliance with healthcare regulations, complete network segmentation.
Critical infrastructure: Air-gap critical systems, multiple defense layers, rigorous OT security practices. You're facing nation-state threats, act accordingly.
Industrial/OT: Balance security with operational requirements. Use passive monitoring that doesn't introduce latency. Don't break production while securing it.
What's the biggest IoT security risk?
Default passwords and missing firmware updates. Attackers exploit these to gain initial access, then move through your network.
How does segmentation improve IoT security?
It isolates IoT devices from critical systems. When a device gets compromised (and eventually one will), segmentation prevents attackers from reaching your important stuff.
What is zero-trust security for IoT?
Zero-trust means no device is trusted by default. Every device continuously proves its identity before accessing anything, regardless of where it's located on your network.
IoT security isn't a one-time project, it's an ongoing process. The attack surface keeps expanding, cyber threats keep evolving, and your security measures need to keep pace.
Start here:
The organizations getting IoT security right aren't the ones with the biggest budgets. They're the ones with visibility into their IoT environments, proper network segmentation, and tools that alert them before small problems become major breaches.
Try PRTG free for 30 days and see exactly what's happening on your IoT network. No credit card required, full functionality, and you'll know within hours what devices you didn't even know existed.