Introduction

If you’re seeing this, you’ve probably come from a sheet of paper that was automatically printed with a link to this blog post. This happened because an automated python script I wrote to automatically find exposed printers found yours and sent this message. Don’t panic—I’m an ethical hacker and I won’t do anything malicious with your printer. Instead, my goal is to show you how simple it is for outsiders to access an unsecured device like yours, and to give you the knowledge you need to lock it down.

Why is this a problem?

Printers are often overlooked when it comes to security, but they are essentially small computers connected to your network. If left unsecured, anyone on the internet can:

• Print unwanted or malicious documents - As you’ve seen, a stranger can easily push content to your printer.
• Access sensitive information - Many printers cache jobs in memory or on internal storage. Documents you’ve printed could potentially be recovered by someone who knows where to look.
• Compromise your network - Printers run firmware, and just like any computer, that firmware can contain bugs. Attackers can exploit vulnerabilities to gain a foothold inside your home or office network.
• Drain your resources - Malicious actors can send hundreds of print jobs, wasting paper, ink, and money.
• Exploit weak configurations - Features like open FTP, Telnet, or unsecured web interfaces make it easy for outsiders to tamper with settings.
• Scale attacks - An unsecured printer can even be recruited into a botnet, used for spam or denial-of-service attacks against others on the internet.

The key point: printers are not just appliances, they are network devices, and any network device that is exposed to the wider internet can be abused. What seems like a harmless issue (someone printing on your machine) is really a signal that your network has a hole in its defenses.

How to secure your printer

Here are the steps you can take right now to secure your printer and prevent unwanted access:

1. Disable remote access - Log into your router or your printer’s web interface and ensure that external (WAN) connections are blocked. Ideally, your printer should only respond to devices inside your home or office network.

2. Change default credentials - Most printers come with predictable usernames and passwords like admin/admin. Attackers scan for these constantly. Change your password to something strong and unique right away.

3. Update your printer’s firmware - Manufacturers release firmware updates to patch vulnerabilities. Visit the official support page for your printer model and install the latest version.

4. Restrict network access - If your router supports VLANs or guest networks, consider putting your printer on its own segment. This limits what an attacker could access if they compromised the printer itself.

5. Disable unused services and protocols - Many printers enable things like FTP, Telnet, or older network printing protocols by default. If you don’t use these, turn them off. Only keep what you need, such as modern secure printing protocols.

6. Enable encryption where possible - Some printers allow encrypted printing (via IPPS or HTTPS). If you have this option, enable it to prevent others from snooping on your print jobs.

7. Use secure printing options - Features like PIN-protected or “hold until released” printing ensure that documents only print when you’re physically at the device. This prevents sensitive information from being left in the tray.

8. Monitor printer logs and alerts - Many network printers keep logs of who accessed them and what jobs were run. Check these occasionally for suspicious activity, and enable email alerts if your printer supports them.

9. Physically secure the printer - In shared spaces, restrict who can physically reach the printer. Someone with access to the machine can sometimes pull memory cards, reset passwords, or otherwise tamper with it.

10. Consider turning it off when not needed - If your printer is only used occasionally, switch it off or disconnect it from the network when idle. An offline printer can’t be hacked.

Conclusion

Your printer may not seem like a prime target, but unsecured devices are low-hanging fruit for attackers. By following the steps above, you make your printer—and your entire network—far harder to abuse. The good news is that most of these fixes only take a few minutes, and once they’re in place, you can use your printer confidently without worrying about outside interference.

Security isn’t about making devices invulnerable; it’s about making them a much less appealing target. Taking a little time today to secure your printer could save you a lot of frustration, wasted money, and potential data exposure later.

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