Seven Reasons the Most Dangerous Device in Your Office Is the One That Just Prints

Ask someone to name the riskiest device in their home office and they'll mention their laptop, maybe their router. Almost nobody says the printer. That blind spot is precisely the problem. Modern printers are full networked computers — running operating systems, holding storage, connecting to Wi-Fi, and occasionally phoning home to their manufacturers — and in most American homes and small offices, they are also the least maintained piece of technology on the premises.

Here's why security professionals take them seriously, and what you can do about it.

1. It's a Computer Nobody Patches

Your printer almost certainly runs a version of an embedded operating system with known vulnerabilities. Unlike your laptop, it doesn't nag you to update. Many owners have never performed a firmware update in the device's entire life. For an attacker scanning a network, an unpatched printer is frequently the softest entry point available.

2. It Remembers Everything You've Printed

Most office-class printers contain an internal hard drive or flash storage that caches print jobs, scans, and faxes — often indefinitely. Tax returns, medical records, contracts, passports: whatever passed through the machine may still be sitting on its storage. When businesses discard copiers without wiping drives, that data goes with them. It has happened at scale: organizations disposing of lease-return multifunction printers have unknowingly donated tens of thousands of stored documents to whoever bought them secondhand.

3. It's a Foothold on Your Network

Once an attacker compromises a printer, they don't stop at printing prank documents. The printer is a trusted insider — a device on your network with connectivity to everything else. It can be used to scan the local network, pivot toward other devices, or intercept print traffic. In well-documented intrusions, printers have served as the beachhead for broader attacks.

4. It Leaks by Design

Printers commonly support legacy protocols — unencrypted printing, FTP, Telnet, SNMPv1 — that transmit data in the clear or expose administrative interfaces. On a home network, an attacker on the same Wi-Fi can sometimes intercept documents in transit or access the printer's embedded web server, which exposes settings, network details, and sometimes stored credentials.

5. It Hears Your Wi-Fi Password

When you set up a wireless printer, you typically entered your Wi-Fi credentials into it — either through its panel or via a setup utility. Those credentials live inside the device. A compromised printer can hand an attacker the keys to your entire wireless network, defeating the one password that protects everything else in your home.

6. It's Exposed to the Internet More Often Than You Think

Search engines that index internet-connected devices have, at various times, revealed hundreds of thousands of exposed printers worldwide — many displaying attacker-written messages on their paper trays simply because the owners could. If your printer's web interface is reachable from the public internet due to router misconfiguration or port forwarding, anyone can find it.

7. It Never Expires

Printers last a decade or more. A device purchased in 2014 may still be chugging along today, running firmware that stopped receiving security updates years ago. Longevity is normally a virtue; in security terms, it's an unmanaged liability.

The Lockdown Checklist

The good news: securing a printer takes under an hour.

• Update the firmware. Check the manufacturer's support page for your model and install the latest version. Enable automatic updates if offered.
• Change the default admin password. Default credentials for popular brands are published in every attacker's toolkit. Set a strong, unique password.
• Disable what you don't use. Turn off FTP, Telnet, and remote printing services. If you never fax, disable the fax board.
• Take it off the public internet. Ensure your router isn't forwarding ports to the printer, and disable Universal Plug and Play (UPnP) if you don't need it.
• Put it on a guest or IoT network. Segmenting the printer from devices holding sensitive data limits the damage if it's compromised.
• Enable encryption. Use WPA2 or WPA3 on your Wi-Fi, and enable encrypted printing where the device supports it.
• Wipe before you dispose. Before selling, recycling, or returning a printer, run the factory reset or storage-wipe function — and for office multifunction devices with hard drives, verify the drive is encrypted or physically removed.

The Bigger Picture

Printers are a case study in a broader blind spot: Americans diligently patch their phones while ignoring the small computers humming in the corner. The same logic applies to smart TVs, security cameras, and routers. Your network is only as strong as the least-attended device on it — and right now, that's probably the one that just printed a grocery list.