A Brief Discussion on Information Security Risks of Printers

 With the advancement of technology, the maturation of the industry chain, and the widespread adoption of commercial applications, laser printers have made tremendous strides in recent years—reducing in size, enhancing performance and functionality, and lowering costs—making them a staple for both business offices and home printing.

  The printer industry has high barriers to entry.

  The global laser printer (including copier) industry has a development history spanning more than 50 years. Although the market size is relatively modest, the industry features high barriers to entry. It was only after Chinese companies broke through export restrictions and entered this sector that, to this day, there are roughly a dozen manufacturers worldwide that have fully mastered the independent research, development, and manufacturing of laser printers. The primary barriers to entry in the printer industry are reflected in the following aspects:

  Patent barriers are high. Globally, there are hundreds of thousands of printer‑related patents, the vast majority filed by U.S. and Japanese companies, with over 200,000 still in force today. Many of these patents do not protect genuine technological innovation; rather, they cover specific technical control methods tailored to particular use cases, yet still qualify for patent protection. Companies file numerous patents on the same technology, function, or component from a variety of angles, creating an impenetrable web of intellectual property that makes it exceedingly difficult for later entrants to break through. For example, regarding automatic duplex printing when the total number of pages is odd, one company has patented “treating the last page as single‑sided,” while another has patented “pre‑inserting a blank page at the end of the document so that the final page is also printed double‑sided.” There are even patents granted for such measures as “the printer retries after detecting a paper‑feed error” or “the fuser stops heating when its temperature exceeds the upper limit and resumes heating when it falls below the lower limit.”

  The technological barriers are high. The development of printers is a complex systems engineering endeavor, with technical expertise spanning more than ten fields, including precision mechanics, fine chemistry, precision optics, electrostatic imaging, integrated circuits, electrical engineering, software engineering, communications engineering, color science, automatic control, and polymer materials. Out of concern for maintaining technological exclusivity, foreign companies are reluctant to cultivate Chinese‑national core technical talent or establish China‑based supply chains for critical components. Moreover, the components used in different printer models often require custom‑designed solutions, and each product typically necessitates the creation of hundreds, sometimes nearly a thousand, sets of molds. The R&D process for every model must accommodate dozens of operating systems on computers and mobile devices, as well as hundreds of application software packages. Testing each printer demands coverage of hundreds of paper types, simulation of thousands of usage scenarios, and execution of tens of thousands of test cases. As a result, breaking through these technical challenges requires substantial human resources, significant financial investment, and an extended development cycle.

  The supply chain is closed. Printer components from different manufacturers lack a unified standard; even among models, parts differ not only in mechanical dimensions and materials but also in numerous physical and chemical parameters related to electrostatic imaging. For core components, printer manufacturers typically develop and produce them in-house or collaborate with overseas suppliers under exclusive agreements, filing extensive patent applications for protection. Even when component suppliers with relevant experience in other industries are willing and capable of developing certain core printer parts, established printer OEMs are reluctant to grant them access to the market. As a result, new entrants into the printer‑OEM space face severe supply-chain challenges right from the outset.

   Printers pose significant security risks.

  Printers are input/output devices that enjoy a high degree of trust from office computers. They not only directly handle confidential print and copy jobs but can also collect users’ sensitive information through software installed on PCs, tablets, or smartphones. All printers are equipped with flash memory, and some high-end models—such as multifunction copiers—often include large-capacity hard drives, effectively turning them into network‑attached storage servers capable of actively gathering user data. Due to the unique functions and usage scenarios of printers, they present more potential avenues for information leakage than computers or mobile phones, making them easier for attackers to exploit. Coupled with their customized, closed operating systems—precluding the installation of antivirus or security‑control software—and the stealthy nature of data‑exfiltration methods, combined with users’ limited awareness of risks and weak preventive measures, there are few effective information‑security safeguards for printers, and those that do exist tend to be inadequate. Consequently, techniques for implanting malicious code into printers or activating existing malware stored within them are numerous and difficult to detect and mitigate. Certain untrusted printers connected to our office networks are akin to dormant cancer cells lurking in our bodies—ready to be activated at any moment, posing threats such as network outages, file deletions, and system crashes. The primary channels through which attackers leverage printers to steal information or launch cyberattacks can be broadly categorized as follows:

  Leveraging the Internet. Many printers come equipped with wired or wireless connectivity—via Ethernet or Wi‑Fi—to enable shared printing and remote printing. After installation, some printers frequently exchange data with overseas servers over the internet. This pathway can be exploited to exfiltrate sensitive user information, as well as to receive remote control commands or malicious code. Even if a printer lacks built-in networking capabilities, it can still join your office network through a computer connected via USB, thereby facilitating shared printing. If any device on the office network is connected to the internet, even a printer without native networking can use that connection as a springboard to communicate with external systems.

  Leveraging the internal network. Whether or not it has network capabilities, a printer can serve as a device connected to the office network. In addition to accessing users’ printed documents, printers may also gain access to unprinted confidential files stored on individual workstations and retain them in their own memory. If vulnerabilities or pre‑configured backdoors in an untrusted printer are discovered and exploited by insiders—such as spies—the data stored on the device can be exfiltrated. Typically, computers trust printers, making them an easy foothold for malicious internal users to bridge between systems, bypass network‑management controls, steal information from other machines, or launch targeted attacks.

  Leveraging consumables and accessories. Most printer consumables are equipped with chips, which typically serve functions such as device identification, print‑count tracking, estimation of remaining consumable life, and retrieval of printing‑control parameters specific to that consumable. In addition to consumables, certain printer accessories may also incorporate similar chips or covertly have wireless chips installed in hidden locations. If a printer designer intends to engage in malicious data exfiltration, they might select chips with large storage capacities and, when necessary, program the printer to offload users’ sensitive information onto those chips. Malicious actors could likewise exploit chips embedded in new consumables or accessories to deliver malware, activation commands, or other payloads to the printer, thereby launching attacks against office networks.

  Take advantage of on-site maintenance opportunities. Prolonged wear can compromise component accuracy, and polymer materials tend to degrade in performance over time. High‑volume, high‑end printers—especially copiers and production‑grade models—require regular maintenance akin to automotive servicing. Printer architectures are complex and vary significantly from one model to another, with few interchangeable parts; consequently, repairing or replacing components is highly challenging. Such maintenance must be performed by external specialists who are thoroughly familiar with the specific model, which poses substantial information‑security risks for users. Printers often include diagnostic interfaces, and may even harbor deliberately concealed communication ports. Test instruments like multimeters and oscilloscopes can be modified to enable communication with the printer, allowing attackers to extract and store data while also injecting malicious code or activating harmful functions. Even more concerning, service technicians might exploit specific key combinations on the printer’s control panel to activate hidden features that were intentionally left enabled.

  By leveraging printer paper, users can add visible watermarks to printed documents when needed. There is also an invisible watermarking technique—steganography—which encompasses methods such as yellow microdots, localized font adjustments, subtle changes in text position or size, and modifications to image halftone algorithms and parameters. If sensitive information is embedded into our printouts using such steganographic techniques, it could pose a risk of data leakage. Furthermore, when we photocopy confidential documents, sensitive keywords within the files may be detected by the printer, enabling eavesdropping or triggering certain hidden malicious functions.

  Installing covert data‑exfiltration devices. Printers with inadequate security protections may have vulnerabilities that hackers can exploit remotely to carry out data theft or launch attacks. Once a printer with insufficient safeguards is disassembled, attackers can modify its firmware to enable data exfiltration and other malicious activities; they might even install a communication module inside the device to transmit user information via wireless signals or power‑line communication, or to send commands to the printer that activate malicious code or harmful functions.

  As printer users—particularly those in organizations with stringent confidentiality requirements—the leakage of information can entail substantial risks or losses. To make our day-to-day information security management more effective, we must not overlook the proper selection and management of printers. The espionage and attack techniques discussed earlier are all carried out through a printer’s software and hardware, and most stem from the deliberate malice of printer manufacturers. Therefore, a printer’s trustworthiness, along with its built-in security enhancements and protective features, should be key considerations when users choose a product. As domestic manufacturers gain greater market presence, user awareness of information security risks continues to rise, and national regulations on the information security of printing devices become increasingly stringent, these latent information‑security threats will gradually recede from the office environment. (Yin Aiguo, Member of the National Information Security Standardization Technical Committee, Member of the Hefei Municipal Political Consultative Conference, and Chief Technology Officer of Nastar Co., Ltd.)

[Editor-in-charge: Tang Binni]

Source: Xinhua Net