CVE-2025-56764 identifies a vulnerability in the login mechanism of the Trivision NC-227WF firmware version 5.80 (build 20141010). The flaw lies in the way the system handles authentication error messages: it returns different responses depending on whether the username exists or not. Specifically, when an invalid username is entered, the system responds with "Unknown user," whereas for a valid username with an incorrect password, it returns "Wrong password." This discrepancy allows an unauthenticated attacker to enumerate valid usernames by analyzing the error messages returned during login attempts. The vulnerability is classified under CWE-204 (Information Exposure Through Discrepancy). The CVSS v3.1 base score is 5.3 (medium severity), reflecting that the attack vector is network-based (AV:N), requires no privileges (PR:N), no user interaction (UI:N), and impacts confidentiality to a limited extent (C:L), with no impact on integrity or availability. While the vulnerability does not directly allow unauthorized access or system compromise, it significantly aids attackers in reconnaissance by confirming valid user accounts, which can be leveraged for subsequent password guessing or social engineering attacks. No patches or fixes have been published yet, and there are no known exploits in the wild. The affected firmware version is 5.80, but no other versions are specified. The vulnerability is relevant for organizations deploying Trivision NC-227WF devices, which may be used in networked environments requiring authentication.

For European organizations, the primary impact of CVE-2025-56764 is the facilitation of user enumeration attacks that can lead to targeted brute-force password attempts or social engineering campaigns. While the vulnerability does not directly compromise system integrity or availability, the exposure of valid usernames weakens the overall security posture and increases the risk of credential-based attacks. Organizations in sectors such as critical infrastructure, telecommunications, government, and enterprises using Trivision NC-227WF devices for secure access could face increased threat levels. The vulnerability could be exploited remotely without authentication or user interaction, making it easier for attackers to gather intelligence on valid accounts. This reconnaissance capability may precede more severe attacks, including unauthorized access or lateral movement within networks. The lack of available patches means organizations must rely on compensating controls until a firmware update is released. Additionally, the exposure of usernames could violate privacy regulations if personally identifiable information is involved, potentially leading to compliance issues under GDPR.

1. Implement account lockout or throttling mechanisms on the Trivision NC-227WF devices to limit the number of login attempts and slow down enumeration attacks. 2. Monitor authentication logs for repeated failed login attempts and unusual patterns indicative of username enumeration or brute-force attacks. 3. Where possible, configure the device or authentication system to return generic error messages that do not differentiate between invalid usernames and incorrect passwords. 4. Network segmentation should be employed to restrict access to the device's management interfaces to trusted administrators only. 5. Use multi-factor authentication (MFA) to reduce the risk of compromised credentials leading to unauthorized access. 6. Engage with the vendor to request a firmware update or patch addressing this vulnerability and apply it promptly once available. 7. Educate users and administrators about the risks of username enumeration and encourage strong, unique passwords. 8. Consider deploying intrusion detection or prevention systems (IDS/IPS) that can detect and block enumeration attempts targeting these devices.