CVE-2023-50916 is a high-severity vulnerability affecting Kyocera Device Manager versions prior to 3.1.1213.0. The vulnerability arises from improper validation and handling of backup location paths configured by administrators. Specifically, the application GUI disallows setting UNC (Universal Naming Convention) paths for backup locations by rejecting backslash characters, which are typical in UNC paths. However, this client-side restriction can be bypassed by intercepting and modifying the request via a proxy or by directly sending a crafted request to the application endpoint, allowing an attacker to set a UNC path as the backup location. Once set, Kyocera Device Manager attempts to verify access to this UNC path by authenticating using Windows NTLM (NT LAN Manager) credentials. This behavior can lead to the exposure of NTLM hashes, which attackers can capture and potentially use for credential relaying or cracking attacks. The vulnerability is classified under CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), indicating a path traversal or path validation weakness. The CVSS v3.1 base score is 7.2, reflecting a high impact on confidentiality, integrity, and availability, requiring low attack complexity but high privileges (administrator-level) and no user interaction. Although no known exploits are currently reported in the wild, the vulnerability poses a significant risk due to the potential for credential theft and lateral movement within networks that use NTLM authentication. The attack vector is network-based, and exploitation requires administrative privileges on the Kyocera Device Manager, which is typically used in enterprise environments to manage Kyocera printing and multifunction devices.

For European organizations, this vulnerability could have serious consequences, especially in environments where Kyocera Device Manager is deployed to manage printing infrastructure. Exposure of NTLM credentials can lead to credential relaying attacks, enabling attackers to impersonate legitimate users or administrators and move laterally within corporate networks. This can result in unauthorized access to sensitive data, disruption of printing and document workflows, and potential compromise of other networked systems. Given that many European organizations rely on Windows-based authentication and network shares for backup and file storage, the risk of NTLM hash exposure is particularly relevant. Additionally, regulatory frameworks such as GDPR impose strict requirements on protecting personal data; a breach stemming from this vulnerability could lead to significant compliance violations and financial penalties. The availability of printing services may also be impacted if attackers manipulate backup configurations or disrupt device management operations, affecting business continuity.

To mitigate this vulnerability, European organizations should: 1) Immediately update Kyocera Device Manager to version 3.1.1213.0 or later where the vulnerability is patched. 2) Restrict administrative access to the Kyocera Device Manager interface to trusted personnel and secure the management network segment to prevent interception and manipulation of requests. 3) Implement network-level protections such as SMB signing and enforce the use of more secure authentication protocols (e.g., Kerberos) instead of NTLM where possible to reduce the risk of credential relay attacks. 4) Monitor network traffic for unusual SMB or NTLM authentication attempts, especially those targeting UNC paths associated with backup locations. 5) Conduct regular audits of backup configurations to detect unauthorized changes to UNC paths. 6) Employ endpoint detection and response (EDR) solutions to identify suspicious activities related to credential theft or lateral movement. 7) Educate administrators on the risks of modifying backup locations and the importance of following secure configuration practices. 8) Consider network segmentation to isolate printing infrastructure from critical systems to limit potential lateral movement.