CVE-2024-12649 is a vulnerability discovered in Canon printers' TrueType Font (TTF) interpreter, specifically within the font hinting instruction processing on the Canon DryOS operating system. The TTF format includes hinting instructions executed by a compact virtual machine to render fonts correctly at various sizes. Researchers found that Canon's implementation does not properly validate stack operations within this virtual machine, allowing a stack buffer overflow when processing maliciously crafted TTF fonts embedded in XPS documents. By sending an XPS file containing such a font to a vulnerable Canon printer, an attacker can trigger arbitrary code execution on the printer's processor. This code execution can be leveraged to establish outbound connections, creating tunnels to attacker-controlled servers, or to intercept and exfiltrate printed documents, posing significant confidentiality risks. The attack vector is notable because it requires minimal user interaction—only that the victim prints the malicious document—and no prior authentication or network exposure is necessary if the attacker can deliver the file internally. Canon recommends restricting printer access to internal networks and applying firmware updates; however, many organizations lack systematic printer firmware management. The vulnerability has a CVSS score of 9.8 according to the researcher, indicating critical severity, although the official CVSS score is not provided in the source. The DryOS architecture limits modern memory protections like ASLR and stack canaries, facilitating exploitation. This vulnerability exemplifies the growing threat posed by specialized office devices lacking endpoint detection and response (EDR) capabilities and highlights the need for comprehensive security beyond traditional endpoints.

For European organizations, this vulnerability presents a serious threat to network security and data confidentiality. Printers are often overlooked in security strategies and may lack EDR and logging, making detection and response difficult. Exploitation can provide attackers with a foothold inside corporate networks, enabling lateral movement to critical servers and workstations. The ability to exfiltrate printed documents is particularly concerning for sectors handling sensitive information, such as legal, financial, and governmental institutions. The attack requires only that an employee print a malicious document, which can be delivered via email or messaging platforms, making social engineering a viable vector. The potential for covert data leakage and network compromise could lead to regulatory violations under GDPR, reputational damage, and financial losses. The lack of widespread firmware update processes for printers exacerbates the risk. Additionally, the vulnerability could be exploited in hybrid scenarios without internet-exposed printers, complicating perimeter defense strategies. Overall, the impact extends beyond printer compromise to broader organizational cybersecurity posture degradation.

1. Immediately apply Canon's official firmware updates for all affected printer models to patch the vulnerability. 2. Implement strict network segmentation to isolate printers from critical network segments and restrict their ability to initiate outbound connections. 3. Disable all unnecessary services and protocols on printers to reduce the attack surface. 4. Enforce strong, unique administrator passwords on all printers and restrict administrative access to trusted personnel only. 5. Remove printers from direct internet exposure by configuring firewalls and access control lists to allow printing only from internal networks. 6. Educate employees about the risks of printing unsolicited or suspicious documents, emphasizing cautious handling of email and messenger attachments. 7. Deploy comprehensive network monitoring and anomaly detection using SIEM solutions to detect unusual printer behavior or network connections. 8. Integrate printers into the organization's asset management and patch management processes to ensure timely updates. 9. Consider deploying endpoint detection and response (EDR) solutions that can monitor network devices or specialized equipment where feasible. 10. Regularly audit printer configurations and logs to identify unauthorized access or suspicious activity.