USB Printer Malware Risks & Protection

TL;DR

Yes, USB printers can be a route for malware infection. They’re often overlooked security weak points. This guide explains the risks and how to protect yourself with simple steps.

Understanding the Risks

Printers have become mini-computers themselves. They contain firmware, storage, and network connections (even if you don’t use them!). This makes them vulnerable. Here’s how malware can get in via USB:

• Firmware Exploits: Hackers can write malicious code directly onto the printer’s firmware.
• BadUSB Attacks: A compromised printer could impersonate a keyboard or network device, installing malware on your computer when plugged in.
• Printer Protocol Vulnerabilities: Some older printing protocols have security flaws that malware can exploit.
• Supply Chain Attacks: Though rare, malware could be pre-installed during manufacturing.

How to Protect Your Printers

Here’s a step-by-step guide to improve your cyber security against USB printer threats:

1. Keep Printer Firmware Updated

1. Check the Manufacturer’s Website: Regularly visit your printer manufacturer’s support website (e.g., HP, Epson, Canon).
2. Download Updates: Look for firmware updates specifically for your printer model.
3. Install Carefully: Follow the manufacturer’s instructions *exactly* when installing firmware. A failed update can brick your printer!

Some printers have automatic update features – enable these if available.

2. Disable Unnecessary Printer Features

1. USB Printing Only: If you don’t need network printing, disable it in the printer settings.
2. Remove Unused Protocols: Older protocols like LPR/LPD are less secure; remove them if possible. Access these settings via your printer’s web interface (usually found by typing its IP address into a browser).

3. Control USB Device Access

Prevent automatic execution of files from USB devices:

1. Group Policy Editor (Windows Pro/Enterprise): Use Group Policy to restrict auto-run functionality.

   gpedit.msc

   Navigate to: Computer Configuration > Administrative Templates > System > Removable Storage Access and disable AutoRun for all drives.

2. Registry Edit (Windows Home – use with caution!): Modify the registry to disable autorun.

   regedit

   Navigate to: HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionPoliciesExplorer and create a new DWORD value named NoDriveTypeAutoRun with a value of 0xFF (disables autorun on all drives). Back up your registry before making changes!

4. Scan USB Drives Before Use

Always scan any USB drive, including those connected to printers, for malware *before* opening files or using the printer.

• Windows Defender: Right-click on the USB drive in File Explorer and select ‘Scan with Microsoft Defender’.
• Third-Party Antivirus: Use your preferred antivirus software.

5. Network Segmentation (Advanced)

If you have network-connected printers, isolate them on a separate network segment.

• VLANs: Create a Virtual LAN (VLAN) for your printers to limit their access to other parts of the network.
• Firewall Rules: Configure firewall rules to restrict communication between the printer VLAN and critical systems.

6. Monitor Printer Activity

1. Printer Logs: Check your printer’s logs for unusual activity (e.g., unexpected firmware changes, large data transfers). Access these via the printer’s web interface.
2. Network Monitoring Tools: Use network monitoring tools to detect suspicious traffic from printers.