CVE-2008-0303 in I-sensys
Summary
by MITRE
The FTP print feature in multiple Canon printers, including imageRUNNER and imagePRESS, allow remote attackers to use the server as an inadvertent proxy via a modified PORT command, aka FTP bounce.
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Analysis
by VulDB Data Team • 07/25/2024
The vulnerability identified as CVE-2008-0303 represents a significant security flaw in Canon's printer firmware that affects multiple imageRUNNER and imagePRESS models. This issue stems from the implementation of the File Transfer Protocol (FTP) print feature, which was designed to facilitate document printing from networked computers to Canon printers. The flaw allows remote attackers to exploit the printer's FTP client functionality to perform unauthorized network operations, effectively transforming the affected printers into unwitting intermediaries in malicious network activities.
The technical root cause of this vulnerability lies in the improper handling of FTP commands within the printer's network stack. Specifically, when a modified PORT command is sent to the printer's FTP client, the device fails to properly validate or restrict the destination IP addresses and ports that can be accessed through its network connection. This allows attackers to leverage the printer's network connectivity to establish connections to arbitrary network destinations, creating an FTP bounce attack vector. The vulnerability is classified under CWE-642, which deals with "External Control of Critical System Resource," as the printer's FTP client is being manipulated to control network access to external systems.
The operational impact of this vulnerability is substantial as it enables attackers to use Canon printers as proxy servers for various malicious activities. An attacker can exploit this weakness to scan network ports, conduct reconnaissance against internal network systems, or even relay other network attacks through the printer. This creates a persistent security risk since the vulnerability exists in the printer's firmware and can be exploited remotely without requiring authentication. The attack surface extends beyond simple port scanning to include potential data exfiltration, command execution, or other network-based attacks that could compromise the entire network infrastructure.
Organizations using affected Canon printers face significant risks from this vulnerability, as it allows attackers to bypass traditional network security controls that rely on perimeter defenses. The printer becomes an unauthorized network node that can communicate with external systems, potentially enabling lateral movement within the network or providing a foothold for more sophisticated attacks. This vulnerability particularly impacts environments where network segmentation is crucial, as the printer can serve as an unexpected pathway for attackers to access restricted network zones. The issue also violates fundamental security principles outlined in the MITRE ATT&CK framework under the technique T1071.004 for Application Layer Protocol: DNS, though in this case the protocol is FTP rather than DNS, the concept of using network services as attack vectors remains consistent.
Mitigation strategies for this vulnerability require immediate firmware updates from Canon to address the flawed FTP client implementation. Organizations should also implement network segmentation and access controls to limit the printer's network access, particularly restricting outbound connections from printer devices. Network monitoring should be enhanced to detect unusual FTP activity patterns that may indicate exploitation attempts. Additionally, administrators should consider disabling the FTP print feature entirely if it is not required for business operations, as this removes the attack surface entirely. Regular vulnerability assessments should be conducted to identify other network-connected devices that may exhibit similar behaviors, and network access control lists should be configured to prevent unauthorized communication from printer devices to sensitive network segments.