How Phishing Attacks Turn to IoT Devices

I’ve been around long enough to witness the evolution of the cyberattack threats over the years — from network worms like Slammer to today’s hyper-targeted phishing attacks. However, I don’t think we discuss often enough how phishing is being used to compromise IoT devices. And that’s a problem.

I just returned from DefCon where I haven’t quite recovered from the hardware hacking village. The ease with which attackers can manipulate IoT devices (using shockingly simple attacks) led me to recall a case I dealt with recently — where a compromised smart printer became the weakest link in a bank’s security. Yep, a printer.

Let’s dissect that: phishing campaigns are no longer just credential theft. And attackers are using them to slip into networks via vulnerable IoT devices. In a world where just about everything — from your office thermostat to your security cameras — is online, that’s terrifying.

Phishing and IoT Breaches: The Connection

When the average person thinks of phishing, they think of an email scam — some kind of fake login page, maybe a bit of social engineering to harvest credentials. That still happens. But now attackers are using phishing to take advantage of poorly secured IoT endpoints as a path into bigger networks.

So here’s what makes IoT such a sweet target:

• Stack piled with default credentials. How many IoT devices still use “admin/admin” to log in? Too many.
• Rarely patched. Most organizations patch their software and OS regularly, what about IoT devices? Those get forgotten.
• Security visibility challenges. Many network security tools were never built to efficiently monitor IoT traffic.
• Human error. This one’s a biggie, as staff phishing pretty much feeds attackers respective security bypassing via unintentional exposure of IoT-based weaknesses.

Attackers don’t need to get through your fancy firewalls if they can get you to log into a dodgy website, one that just exfiltrates credentials for a connected IoT hub, camera, or even a VoIP phone. Once inside, they still switch to the broader corporate network.

And believe me, this is not hypothetical. It’s happening right now.

Case Studies: Where IoT Meets Phishing

Case 1: The Smart Printer That Unlocked the Network

We received a call from a mid-sized bank that had detected unauthorized activity in their internal systems. It transpires that an employee had been the target of a phishing email, disguised as coming from IT support. The dispatch included a link to update the “printer firmware” — but it turned out to be malware that provided the attackers a direct line to the smart printer.

They pivoted from there, ultimately gaining access to financial data before we were brought in to help contain the breach. And the worst part? The printer had a known, unpatched vulnerability. No fancy cyberattack—just a phish and a long-standing firmware flaw.

Case 2: Recon and Persistence via VoIP Phones

Another client — we’ll call them Company X — were besieged by phishing emails aimed at their helpdesk staff. Some employees had clicked through a fake login page that collected their credentials.

Sounds familiar: a phishing attack, right? Except the attackers then used those credentials to sign into the company’s VoIP admin panel, where they:

• Created new VoIP accounts acting as back doors.
• Audited internal conversations for sensitive topics.
• Phished other employees via the hacked VoIP system with seemingly internal-looking messages.

A phone system had become the attacker’s fortress—all due to a phishing email.

How Can IoT Be Protected Against Phishing Attacks?

Before I sound off on IoT security hygiene (because come on, why are we still using default creds?), let’s run through what you can actually do to stop this.

1. Assign Basic IoT Security Hygiene

• Change default passwords. First thing. No exceptions.
• Isolate IoT devices to dedicated VLANs/subnets; they should not be on the same network as systems that are critical to operations.
• Patch those devices. Yes, including the ones you haven’t thought about since you installed them.

2. Enhance Authentication and Access Control

• Use MFA whenever possible, including IoT platform logins.
• Turn off features for remote access you do not use.
• Limit access to the IoT management interfaces. Your friend here is least privilege.

3. Educate Employees About Phishing

• Conduct simulated phishing attacks. Test employees (but don’t shame them — educate them).
• Train staff to identify domain impersonators in email.
• Enforce reporting culture — ask instead of clicking naively.

4. Monitor IoT Traffic and Behavior

• Network segmentation — so a hacked IoT device cannot access everything.
• Zero-trust tenets — don’t assume an IoT device should always have open access.
• Behavior analytics — to determine when IoT devices start behaving strangely (talking suddenly to IPs in Russia, for example).

Awareness Training: The Final (and Often Most Effective) Layer of Defense

Well, here’s the thing: there’s no alternative to human awareness for a security solution.

Phishing training should be dynamic, continuous, and adaptive, rather than simply an exercise that takes place once a year.

• Instruct them to develop a healthy skepticism — employees should question unexpected appearances of login prompts and software update requests.
• Tell staff why IoT security is important — so they don’t dismiss warnings to update their printers.

And if you take away nothing else from this article, take this: never think your IoT devices are too small to be targets. Reason enough for attackers not to care about the device itself. What they care about is using that device to get into your network.

Quick Take: What to Do Immediately

• Change passwords for all IoT devices. If it’s still on “admin/admin,” you’re asking for trouble.
• Segment your IoT network. Lock those devices out of important infrastructure.
• Deploy phishing awareness training. Your workers are your front line — and often weakest — line of defense.
• Review configurations of all IoT devices and apply firmware updates. All vulnerabilities are like an open door.

Final Thoughts

I first got into networking in the ’93 era, when the biggest attack we faced was a noisy network worm. Now? Attackers are creatively exploiting human error, combining phishing and IoT vulnerability in order to compromise systems while avoiding alarm bells.

And it’s working.

I watch as companies spend millions on expensive AI-infused security solutions (don’t get me started) without doing the basics — patching out-of-date firmware, restricting access to IoT management consoles, and training employees to recognize scams.

But how to avoid IoT phishing attacks? Focus on fundamentals. As attackers don’t need rancid exploits, only a single unpatched, unmonitored device and a well-written email.

Stay safe. And for security’s sake, please update your IoT devices.