That Smart Device You Love? It's Probably Spying On You

Just came across some alarming security news today that should make anyone with a “smart home” reconsider what they’ve plugged into their walls.

Here’s the deal: there’s this tiny chip called the ESP32 that’s in literally BILLIONS of devices—smart plugs, lights, cameras, thermostats, you name it. It’s cheap, it works, and apparently, it’s been hiding a secret backdoor this whole time.

Spanish researchers from Tarlogic Security just blew the lid off this at RootedCON. They found 29 hidden commands buried in the Bluetooth firmware that let anyone with the know-how completely take over these devices. We’re talking straight-up surveillance capabilities built right into the hardware that’s probably scattered all over your house.

What’s Actually Happening Here?

Let me break down what this means without the usual tech media sugar-coating:

This isn’t just a “vulnerability” or a “bug.” This is a fucking backdoor—or at least functions exactly like one. Hidden from documentation. Accessible through a special command code (Opcode 0x3F for those keeping score).

To be fair, Espressif claims these are “internal debugging commands” that weren’t meant to be accessible. But intention aside, the security implications are the same: a massive attack surface nobody knew about.

What can someone do with these hidden commands? Glad you asked:

  • Spoof MAC addresses (pretend to be trusted devices)
  • Inject whatever packets they want (bypass security)
  • Manipulate memory directly (install persistent malware)
  • Pivot through your network (compromise everything)

One important clarification: this isn’t typically exploitable remotely over the internet. An attacker would need to be within Bluetooth range of your device. That’s still concerning for physical security, shared spaces, and apartments, but it’s not like someone in Russia can instantly hack your smart plug.

I’m not typically one for conspiracy theories, but when a Chinese-made chip that’s in a billion devices has undocumented commands that provide surveillance capabilities… well, even if it’s just negligence, the impact is still massive.

It’s In Everything

The truly unsettling part is how ubiquitous this chip is. The ESP32 is basically the default microcontroller for budget IoT devices. It’s in:

  • Those cheap smart plugs you got in a 4-pack on Amazon
  • Budget smart light systems
  • Temperature sensors
  • Security cameras
  • Smart locks (yes, seriously)
  • Baby monitors
  • Some medical devices (terrifying)

If it connects to your WiFi, costs under $50, and was made in the last few years, there’s a decent chance it’s running this chip.

So What Now?

This is where it gets frustrating. Espressif finally issued a statement claiming these were debug commands never intended for production firmware, and promising patches. But that still leaves us:

  1. Wondering how debug commands this powerful made it into production devices
  2. Waiting for device manufacturers to release firmware updates (which many never will)
  3. Hoping for some actual accountability (not holding my breath)

If you want to see the technical details of how researchers discovered this, check out this presentation:

In the meantime, what can you do? Some ideas:

  • Segment your network if you can (put IoT devices on a separate network)
  • Disable Bluetooth on devices when not actively using that feature
  • Be extra skeptical of devices handling sensitive info or controlling access to your home
  • Update firmware on anything that gets an update

The reality, though, is that most affected devices will never get fixed. They’re abandoned by manufacturers, or the companies just don’t care enough to push updates.

The Bigger Picture

This isn’t just about one chip. It’s about the entire model of cheap, insecure devices we’ve welcomed into our homes without question. It’s about supply chains without oversight and corporations without accountability.

Remember when people thought it was paranoid to worry about smart devices spying on you? Turns out the paranoid folks were right all along.

I’m not saying throw everything out and go live in a cabin in the woods (though some days it’s tempting). But maybe—just maybe—we should be a little more careful about what we connect to our networks. Maybe convenience isn’t always worth the trade-off.

For now, I’m taking a hard look at every “smart” device in my house and asking whether I really need it. Maybe you should too.

What smart devices do you have that might be using this chip? How concerned are you? Drop your thoughts in the comments – I’m especially interested in hearing from security folks who’ve been tracking this.