What IoT Devices Are Spying on You (And How to Stop Them)

 

What IoT Devices Are Spying on You?

IoT devices are everywhere. Your home probably has at least a dozen of them — a smart speaker on the kitchen counter, a thermostat that "learns" your schedule, a doorbell camera watching the front porch, maybe a fitness tracker on your wrist. According to research cited by NordVPN, nearly 90% of households have at least one IoT device. Most people have far more than that.

What most of us don't realize is that these gadgets are doing a lot more than just making life easier. They're collecting data constantly — your voice, your location, your daily routine, your sleep patterns, even your home's energy usage. And that data flows to company servers, sometimes to third parties, occasionally to advertisers, and in some cases to law enforcement — all without you clearly understanding what you agreed to.

That's not a conspiracy theory. It's how the IoT privacy landscape actually works right now. The business model for many smart device manufacturers depends on data collection. The device is the product, but your behavior is the commodity.

This article breaks down exactly which smart home devices are most likely spying on you, what data they're actually capturing, and the specific steps you can take to lock things down without throwing your gadgets in the trash.

What Does "Spying" Actually Mean in the IoT World?

Before jumping into device-specific risks, it's worth being precise about what IoT surveillance and data collection actually look like in practice.

Most connected devices aren't sending your conversations to foreign governments. What they're doing is arguably more insidious: building detailed profiles of your behavior, preferences, and routines — then monetizing that information.

Data collection by IoT devices typically includes:

• Voice recordings and command history
• Location data and movement patterns
• Sleep and health metrics
• Viewing habits and content preferences
• When you're home and when you're not
• Energy usage patterns (which reveal behavioral routines)
• Device interaction logs and timestamps

The issue isn't just what companies do with this data internally. Device vendors share data not only throughout their own business units but also with downstream third parties — including cloud services, government agencies, insurance companies, law enforcement, data aggregators, and social media platforms. Once data leaves the device, users have essentially lost all control over how it gets used.

That's the real risk. And it starts with understanding which devices are most aggressive about it.

The 7 Most Dangerous IoT Devices Spying on You Right Now

1. Smart Speakers and Voice Assistants

This is the most obvious one, but the reality is worse than most people assume.

Smart speakers like Amazon Echo, Google Nest Audio, and Apple HomePod are always listening. They have to be — that's how they catch their wake words. The problem is that this "always-on listening" doesn't work perfectly. Devices regularly activate on sounds that merely resemble their trigger words, capturing and storing snippets of conversations that were never meant for them.

Amazon admitted that human employees review Alexa recordings for "quality control" purposes. Google has done the same. Even Apple had to pause its Siri review program after it emerged that contractors were listening to accidental activations — including sensitive private conversations.

Some devices have been found to not only be listening continuously but also retaining recordings of everything said within their range.

How to reduce the risk:

• Go into your Alexa or Google Home app and delete your voice history regularly
• Disable the microphone when you're not actively using the device (most have a hardware mute button)
• Review and turn off "Use voice recordings to improve" settings
• Consider whether you actually need the device at all

2. Smart TVs

Your television is watching you back. This isn't a metaphor.

In 2017, the US Federal Trade Commission reported that Vizio was gathering data on what people were watching without their consent and selling it to advertisers. Vizio got caught and faced consequences, but the underlying practice hasn't disappeared — it's just become more normalized and buried in terms of service.

Modern smart TVs use a technology called Automatic Content Recognition (ACR), which captures a sample of whatever is on screen — whether it's a streaming service, a cable box, or a Blu-ray player — and sends it back to servers to identify what you're watching. This data is then used for targeted advertising.

If your TV connects to the internet for streaming services, it's very possibly using that same connection to report back and sell your viewing habits to marketers. These services will let you turn off this surveillance, but you have to dig into the settings submenus.

How to reduce the risk:

• On Vizio TVs: turn off "Smart Interactivity" and "Viewing Data"
• On Amazon Fire TVs: disable "Collect App and Over-the-Air Usage Data" and "Internet-based Ads"
• On Roku devices: enable "Limit ad tracking"
• On Samsung TVs: disable "Viewing Information Services" in the privacy settings
• Consider connecting only a dedicated streaming stick rather than using the TV's built-in smart features

3. Smart Doorbells and Security Cameras

Smart doorbells like Ring and Nest Hello collect a striking amount of data. Every time someone approaches your door, their image is captured. Audio is recorded. Motion events are timestamped. Facial recognition may be applied. And all of it flows to the cloud.

Ring has been questioned for sharing video recordings with police departments and third-party service providers such as Facebook and Google without user knowledge or consent. The Federal Trade Commission also charged Ring with violating user privacy by allowing employees unrestricted access to customer video recordings, including footage from bathrooms and bedrooms.

The broader concern isn't just what the company does with your footage. It's that any IoT security camera with weak authentication or outdated firmware is potentially accessible to anyone who finds a vulnerability.

In August 2024, thousands of consumers reported unauthorized access to their smart home devices, including locks, security cameras, and thermostats. Hackers exploited weak passwords and default settings to gain control over devices and breach privacy.

How to reduce the risk:

• Set a strong, unique password for your camera account
• Enable two-factor authentication
• Review who has access to your footage in the app settings
• Opt out of any footage-sharing programs with third parties
• Keep firmware updated

4. Smart Thermostats

Your thermostat knows more about your home life than you might think.

A smart thermostat tracks when you wake up, when you leave, when you come home, and when you go to sleep — every single day. That behavioral data can be used to infer your income level, your work schedule, whether you're on vacation, and even how many people live in your home.

In 2018, Google Home and Chromecast were found to reveal a user's physical location to within 10 meters. While that specific vulnerability was patched, it illustrates how even seemingly mundane smart home devices can expose precise personal information when security isn't prioritized.

The Ecobee Smart Thermostat gives data access rights only to California residents. If you're from any other US state, you may have no clear avenue for accessing or deleting the personal data the device has collected about you.

How to reduce the risk:

• Check your thermostat's privacy settings and data-sharing options
• Use a local hub-based system where possible to limit cloud data transmission
• Review what third-party integrations your thermostat is connected to and remove ones you don't use

5. Fitness Trackers and Smartwatches

Fitness trackers and smartwatches collect some of the most intimate data of any consumer device: heart rate, sleep cycles, menstrual cycles, blood oxygen levels, stress levels, location history, and workout data.

This health data is genuinely sensitive. Insurance companies have expressed interest in behavioral and health data for risk assessment purposes. The risk of that data being sold, breached, or subpoenaed is real — and the data privacy protections around health data from fitness devices are considerably weaker than those covering medical records.

Several fitness tracking companies have faced scrutiny after military personnel inadvertently revealed sensitive base locations through publicly visible running route data. The same principle applies to civilians: your daily running route, your commute pattern, and your home address can all be inferred from fitness tracker GPS data.

How to reduce the risk:

• Disable GPS tracking when you don't need it
• Opt out of data sharing with third parties in the app settings
• Review whether your health data is being shared with insurance partners
• Use a reputable brand with a clear, transparent privacy policy

6. Smart Plugs and Smart Lighting

These seem harmless, but smart plugs and connected bulbs can reveal your daily routine in surprising detail. Which lights turn on and off, and when, tells a story about your schedule, your sleep habits, and whether you're home.

In 2024, India's CERT-In found a vulnerability in Philips Smart Lighting products where the devices were storing sensitive Wi-Fi credentials in their firmware, creating the potential for compromise of personal information and other connected networks.

Beyond security vulnerabilities, the data collected by smart lighting ecosystems flows to company servers and is subject to the same data-sharing policies as any other IoT device.

How to reduce the risk:

• Use smart plugs and bulbs that support local control (Zigbee or Z-Wave protocols, for example, can work without cloud connectivity)
• Keep firmware updated
• Use a separate network segment (guest network or IoT VLAN) for these devices

7. Baby Monitors and Smart Nursery Devices

Smart baby monitors with video and audio capabilities are among the most sensitive devices in any home — and among the most frequently targeted by hackers looking for access to live video feeds.

These devices often have weak default credentials and infrequent firmware updates. Parents are understandably focused on watching their child, not on network security. But an unsecured baby monitor is essentially a live-streaming camera inside your home, accessible to anyone who finds the right credentials or exploits an unpatched vulnerability.

How to reduce the risk:

• Immediately change the default username and password
• Enable encryption if the device supports it
• Keep firmware updated
• Place the device on a separate network from your main devices
• Check the manufacturer's history on issuing security patches

Why IoT Privacy Risks Are Harder to Manage Than You Think

Part of what makes IoT security uniquely challenging is the sheer number of devices involved and how little visibility most users have into what those devices are doing.

Users are often completely unaware that IoT devices are collecting, using, and sharing their personal data — or only marginally informed if they consented to a connection but never read the associated privacy policies.

There's also the cross-device profiling problem. Your smart TV knows what you watch. Your smart speaker knows what music you like and what questions you ask. Your thermostat knows your schedule. Your fitness tracker knows your health. When a company — or a data broker that buys from multiple companies — combines all of this, the resulting profile is extraordinarily detailed.

Tech companies have been creating increasingly comprehensive user profiles spanning data from a multitude of different sources, often referred to as "big data." Smart home data is particularly powerful because of how it can interact with other information gathered online — including purchase data, search history, and mapping data — to predict and profit from users' behavior.

Additionally, many IoT devices are essentially impossible to update or patch once a manufacturer stops supporting them. Devices may outlive their security support cycles, remaining active long after updates stop. These factors make IoT data harder to monitor, classify, and secure.

How to Stop IoT Devices from Spying on You: 8 Proven Steps

Step 1: Audit Every Device on Your Network

You can't protect what you can't see. Start by making a list of every connected device in your home. Most routers have a device list in their admin panel. Tools like Fing (available as a free app) can scan your network and show you every device connected to it.

Once you have the list, ask yourself: does this device need internet access to do its job? A smart plug that just switches power on and off doesn't necessarily need to call home to a server in another country.

Step 2: Segment Your Network

One of the most effective IoT security measures you can take is setting up a separate network for your smart devices. Most modern routers support a guest network or, if you're more technical, a dedicated VLAN for IoT devices.

The logic is simple: if a hacker compromises your smart thermostat, you don't want them to have access to the same network as your laptop and phone. Network segmentation keeps your IoT devices isolated from your sensitive data.

Step 3: Change Default Passwords Immediately

Manufacturers often assign basic, easily guessable usernames and codes to devices during production. Commonly used defaults like "admin" or "password" fail as an adequate defense against cyberattacks.

Every single IoT device in your home should have a unique, strong password. Use a password manager to keep track of them. Enable two-factor authentication wherever it's supported.

Step 4: Keep Firmware Updated

Outdated firmware is one of the most common ways hackers get into smart home devices. Manufacturers release security patches to fix vulnerabilities — but only if you install them do they actually protect you.

Set up automatic updates where available. For devices that don't support auto-updates, put a recurring reminder on your calendar to check for firmware updates every few months.

Step 5: Review App Permissions and Privacy Settings

Every smart home device comes with an app, and those apps request permissions. Go through each one and ask: why does my smart lightbulb app need access to my contacts? Why does my thermostat app need my camera?

In the privacy settings of each app and device, look for options to:

• Opt out of data sharing with third parties
• Disable targeted advertising
• Delete your voice or usage history
• Limit data collection to what's strictly necessary

Step 6: Disable Features You Don't Use

Many smart devices come loaded with features you'll never use — features that nonetheless collect data. If you don't use Alexa's drop-in calling feature, turn it off. If you don't need your TV's microphone for voice control, disable it.

Every disabled feature is one less data collection vector.

Step 7: Read the Privacy Policy (Yes, Really)

This sounds painful, and the full text often is. But most privacy policies now include a summary or key points section. At minimum, look for answers to these questions:

• What data is collected?
• Who is it shared with?
• Can you request deletion of your data?
• Does the company sell your data to third parties?

If a company's policy doesn't clearly answer these questions — or if the answers are alarming — that's worth weighing before you buy or keep using a device.

For guidance on evaluating IoT device privacy policies, the Electronic Frontier Foundation's Surveillance Self-Defense guide is a reliable, practical resource.

Step 8: Consider a Hardware Firewall or Pi-hole

For more technically inclined users, a Pi-hole or similar DNS-level ad and tracker blocker can be set up on your home network to block outgoing connections from IoT devices to known tracking and advertising domains. This doesn't eliminate all data collection, but it reduces the volume of data leaving your network considerably.

The Mozilla Foundation's Privacy Not Included guide also provides independent privacy assessments of popular smart home products — useful for deciding what to buy in the first place.

The Regulatory Landscape Around IoT Data Privacy

It's not just up to individual consumers. The legal environment around IoT device privacy is shifting, though progress is uneven.

The 2024 EU Cyber Resilience Act establishes cybersecurity requirements for digital products sold in the EU, including IoT devices. The US government advocates for plain language in IoT privacy policies as a Federal Acquisition Regulation requirement, based on the IoT Cybersecurity Improvement Act of 2020.

In the US, California's Consumer Privacy Act (CCPA) gives California residents specific rights to access and delete their data. The gap between those protections and what's available to residents of other states remains significant.

Until comprehensive federal data privacy legislation passes — and there's no guarantee of when that happens — the burden of protection falls largely on individuals.

Conclusion

IoT devices have made daily life genuinely more convenient, but that convenience comes at a price that most people haven't fully calculated. Smart speakers, connected cameras, TVs, thermostats, fitness trackers, and even lightbulbs are continuously collecting data about your behavior, preferences, health, and home life — and much of that data flows to third parties without your meaningful consent. The good news is that you're not powerless. By auditing your devices, segmenting your network, changing default passwords, reviewing privacy settings, keeping firmware updated, and using independent resources like the Mozilla Privacy Not Included guide and EFF's Surveillance Self-Defense, you can significantly reduce your exposure without giving up the technology you actually find useful. IoT privacy isn't about paranoia — it's about making informed decisions and taking reasonable steps to stay in control of your own data.