Apple @ Work: Why Your Printer Is the Least Secure Device on the Network

The Overlooked Threat

When security teams inventory their attack surface, they usually think of servers, endpoints, cloud identities, and mobile devices. Very few organizations treat the office multi-function printer (MFP) as a first-class security citizen. That is a big mistake. Printers share the same network as everything else, yet they are often exempt from patching programs, segmentation policies, and monitoring — exactly the kind of neglect attackers love.

In the context of Apple-centric enterprises, where device management like Apple's DEP and identity-based security are mature, the printer remains a throwback. AirPrint makes it trivial to send a document to a printer, but the services that enable that convenience also provide a gateway for malicious traffic. If a single printer is compromised, it can become a pivot point into servers, file shares, or even cloud management APIs.

Why Printers Are Uniquely Insecure

There is no single design flaw that makes printers the least secure piece of equipment. Rather, a combination of factors creates a uniquely bad risk profile.

Firmware Neglect

Unlike laptops that receive monthly security updates, printers often go years without a single patch. Many IT organizations treat a printer like a household appliance: plug it in, configure it once, and forget it. Vendors themselves often provide only sporadic firmware fixes with no formal security advisory channel. When a critical vulnerability is disclosed, the response is too slow to stop active exploitation. End-of-life printers are even worse — they receive zero updates, leaving known holes open indefinitely.

Default Credentials and Open Protocols

Out of the box, printers tend to have simple administrative interfaces with default credentials like "admin:password" or "admin:1234." Attackers scan for devices with open port 9100 (raw printing), 515 (LPD), or 631 (IPP) and try those defaults. Even when credentials are changed, embedded web servers often expose verbose system information that aids further attacks.

Positions of Privilege on the Network

Printers are not placed in a locked-down corner. They sit inside office rooms, usually on the same subnet as workstations. From there, they can initiate outbound connections, receive unsolicited inbound traffic, and communicate with any other device on the network. This is a violation of the zero-trust principle: every device should only have the access it absolutely needs. Printers rarely need to talk to every employee computer, much less to all servers or the internet.

Apple Enterprises Are Not Exempt

It may be tempting to think that an all-Mac environment is inherently more secure. That's true for the endpoints themselves, but printers are platform agnostic. An AirPrint printer uses Bonjour to advertise its services, which makes it easy for any Mac, iPhone, or iPad to find it. The problem is that Bonjour discovery also works for attackers who are already on the local network. They can enumerate printers and attempt to access management interfaces without even looking suspicious.

Moreover, as Apple continues to promote a connected ecosystem, more and more devices are being brought into the corporate fold. That means more data flowing through printing workflows, and more opportunities for a compromised printer to eavesdrop or exfiltrate sensitive documents. The printer is no longer just a piece of paper-moving hardware; it is a network endpoint with full visibility into the office.

Hardening the Least Secure Device

Thankfully, there are straightforward steps that can remove most of the risk without sacrificing productivity.

• Place printers on an isolated VLAN or a dedicated print network with strict firewall rules. Allow only specific, required communications such as print jobs from authorized devices and management traffic from an admin subnet.
• Create a firmware update schedule. As with operating systems, assign a quarterly or even monthly reminder to check for and deploy printer patches. Make it part of the standard lifecycle management process.
• Disable all unused services, including FTP, Telnet, HTTP if not needed, and raw port 9100 when network printers can use more secure protocols like IPPS. Also restrict SNMP and community strings to read-only.
• Change default passwords on all printing devices and require strong administrative credentials. Use central vaults or directory services to manage them.
• Enable logging and integrate printers with your security information and event management (SIEM) tool. Watch for unusual burst printing, admin logins outside business hours, and outbound scan behavior.
• Perform an annual printer security assessment. This should include reviewing the manufacturer's security advisories, evaluating model EOL status, and checking the device's config against a baseline. When replacing printers, insist on those with verifiable update commitments and secure boot capabilities.

Beyond configuration changes, enterprises should also think about the physical security of printers. Many devices have removable hard drives that store print job images, so decommissioning procedures must include secure disk wiping. In shared or open areas, printing should require authentication at the device, like badge release or a PIN, to prevent sensitive documents from being left in the tray.

Beyond the Box: Culture and Policy

Securing printers is not entirely a technical problem. The reason they remain insecure is often cultural. In many organizations, printers are managed by facilities or office managers, not by security teams. That makes them absent from the asset list and security roadmap. To fix that, assign explicit ownership of printer security to the IT operations team and make sure they have the budget and mandate to act.

It is also worth rethinking printable data. Print jobs often contain personally identifiable information, financial records, or proprietary documents. Many modern printers store images to disks, which can be accessed after decommissioning. Strong policies on device decommissioning, disk wiping, and secure pull printing will go a long way to reducing risk.

Education is equally important. Users should not be able to bypass security measures or install third-party drivers that open up other vectors. In an Apple-centric environment, administrators can leverage profiles to restrict AirPrint device discovery and enforce encryption for Apple devices communicating with printers. However, those settings only protect the Apple side; the printer itself remains vulnerable if it is not hardened and patched.

The Path Forward: Building a Complete Defense

As this exploration suggests, printers are the least secure piece of equipment in most organizations not because they are inherently evil, but because they are ignored. Attention brings progress. For Apple administrators particularly, the roadmap is clear: integrate printers into the enterprise security posture, demand secure defaults, and enforce governance with the same rigor applied to Macs and iPhones. Once that happens, the printer will no longer be the soft spot in otherwise robust defenses.

In an era where attackers are continuously looking for weak points, leaving a whole class of devices unmanaged and unpatchable is not just an oversight — it's an invitation. The next time you walk past the office printer, take a second look. It may be the most dangerous piece of equipment you have.

This article is based on reporting by 9to5Mac. Read the original article.