Summary
In modern IT infrastructure, companies invest millions in firewalls, endpoint protection (EDR) on laptops, and strict access control on servers. But in the corner of the architectural firm, the construction trailer, or the reprography department stands an A0 plotter. Often this is seen as “just a printer”. In reality, it is a powerful computer with its own Linux or Windows IoT operating system, a 500GB hard drive, and a direct internet connection.
The problem? Often this machine is still on the standard factory settings (admin/admin or 123456) and has not been patched for years. For hackers, this is the ideal backdoor. In this article, we dive into the mindset of the cybercriminal and explain how to turn your plotter into an impregnable fortress.
The Anatomy of an IoT Attack
Every device with an IP address is a potential target. Printers, cameras, smart thermostats – the Internet of Things (IoT) is often “insecure by design” or “insecure by configuration”.
The Shodan Search Engine
Hackers don’t even need to know your company name to find you. They use search engines like Shodan. It continuously scans the internet for open ports and specific device characteristics (“banners”).
A search like port:9100 org:"Large Construction Company Ltd" can yield immediate results. There are thousands of open plotters to be found, directly accessible from the public internet, often without a password. A hacker can literally see, download, or manipulate your prints without you noticing.
What can a hacker specifically do with a plotter?
It goes much further than the “funny” scenario where someone prints a smiley. Plotters are strategic assets.
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Reconnaissance & Pivot (The Stepping Stone): This is the greatest danger. Because printers are often on the same internal network segment (VLAN) as the architects’ workstations or the administration’s servers, the hacker uses the printer as a “beachhead” or stepping stone.
- Step 1: He infects the printer via a known vulnerability (e.g., a buffer overflow in the PostScript interpreter).
- Step 2: The printer becomes his base of operations. The printer is rarely scanned by antivirus software and has 24/7 power.
- Step 3: From the printer, he scans the internal network. He attacks lateral targets such as the Active Directory server, the NAS with project files, or the accounting software.
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Data Exfiltration (Industrial Espionage): The memory and hard drive of the plotter often store prints from the past few days or weeks in a “Job History”.
- What’s on there? Top-secret plans of data centers, prisons, bank buildings, or confidential urban renewal projects.
- For a competitor or foreign power, this information is worth its weight in gold. The hacker silently downloads the PDFs via the web interface.
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Botnet Participation: Printers have powerful processors. Malware like Mirai turns the printer into a zombie in a botnet. Your plotter then helps take down bank or government websites via DDoS attacks, which can land your IP address on a blacklist.
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Sabotage (Denial of Service): In a “burn-out” attack, a hacker can instruct the printer to continuously print completely black pages, or to constantly heat the fuser (the oven) until the machine overheats and fails. This halts your production at critical moments.
The Solution: Hardening Your Plotter (Technical Guide)
The good news is that modern business plotters (like the HP PageWide XL, DesignJet T1600/T2600, and Z-series) have the necessary enterprise-grade security features on board. The problem is that they are often turned off. Here is your step-by-step plan for “Hardening”.
Step 1: Identity & Access Management (IAM)
The most common mistake is leaving default passwords.
- Administrator Password: Set a strong password on the EWS (Embedded Web Server) immediately. Minimum 12 characters, complex.
- No Shared Accounts: Create separate accounts for administrators if possible, instead of one generic admin account.
- Disable the ‘Guest’ account: Ensure that anonymous users cannot change settings.
Step 2: Minimize the Attack Surface (Port Closing)
A printer has dozens of network ports open (“services”) by default for maximum compatibility with old systems. In 2026, you don’t need these anymore.
- FTP (Port 21): Insecure, sends data in plain text. OFF.
- Telnet (Port 23): Heavily outdated command-line protocol. OFF. (Use SSH if necessary).
- HTTP (Port 80): Unencrypted web traffic. Force a redirect to HTTPS.
- RAW Print (Port 9100): The standard print port, but often unsecured. Consider IPPS (Secure Printing, port 631) which uses SSL/TLS.
- Legacy Protocols: AppleTalk, DLC/LLC, IPX/SPX. If you don’t have a Macintosh from 1995, turn this off.
Step 3: Encryption and Certificates
Ensure that the communication between the PC and the printer cannot be intercepted (“Man-in-the-Middle” attack).
- Self-Signed vs CA-Signed: By default, a printer uses a “Self-Signed Certificate”. This gives an error message in the browser (“Not secure”). Install a valid certificate signed by your own Certificate Authority (CA) or a trusted issuer.
- TLS Version: Disable TLS 1.0 and 1.1 (these are cracked). Allow only TLS 1.2 and 1.3 for HTTPS and IPPS connections.
Step 4: Network Isolation (Segmentation)
NEVER put printers directly on the internet (no Port Forwarding in the router!).
- Place printers in a separate VLAN (Virtual Local Area Network) for peripherals.
- Configure Access Control Lists (ACLs) on the switch so that only the Print Server and certain management PCs can communicate with the printer VLAN. Clients (laptops) only talk to the Print Server, not directly to the printer.
Step 5: SNMPv3 for Monitoring
Simple Network Management Protocol (SNMP) is used by tools like HP Web Jetadmin or your IT dashboard to read ink levels.
- Versions 1 and 2 (v1/v2c) are insecure; the “community string” (password) goes unencrypted over the line.
- Use exclusively SNMPv3. This supports authentication (SHA) and encryption (AES-128/256).
HP Security Specific: Connection Inspector & Whitelisting
HP plotters have unique features that go beyond standard hardening.
- HP Connection Inspector: The printer uses machine learning to learn normal network behavior. If the printer suddenly tries to connect to a suspicious DNS address (e.g., a known malware server), it intervenes and restarts itself.
- Whitelisting: The printer only loads firmware that is digitally signed by HP. If malware tries to overwrite the firmware, the chip refuses it.
Business Fundamentals: Risk Management & Compliance
Why invest time and money in securing a printer?
- ISO 27001: If your company is ISO 27001 certified (or wants to be), you must secure all assets in your scope, including printers. An auditor will check for this.
- Supply Chain Security: Large clients (government, defense, large contractors) increasingly demand that their suppliers (you) be cybersecure. A hack via your printer can lead to exclusion from future tenders.
- The Costs of a Leak: The average cost of a data leak is €150 per record. But the reputational damage is immeasurable. If it leaks that you couldn’t secure your customers’ plans, you lose the trust of the market.
Europlan Service: Secure Deployment
We understand that you are an architect or contractor, not a cybersecurity expert. Therefore, we deliver printers “Secure”.
- Firmware Updates: We ensure the machine has the latest patches upon installation.
- Security Policy: We set up the printer together with your IT department. We can create a configuration file that we roll out to all your printers, so they all have the same, safe settings.
- Nightly Reset: With HP Security Manager software, we can set the printer to check its security settings every night (‘Self-healing’). If someone accidentally turned on Telnet during the day, the software turns it off again at night.
Conclusion: Treat the Plotter Like a Server
A modern large format printer is no longer a peripheral. It is an advanced network endpoint that deserves the same diligence, monitoring, and security as your servers and laptops.
Is your printer fleet an open target? Don’t leave it to chance.