CVE-2021-45035 is a vulnerability identified in Velneo vClient version 28.1.3, categorized under CWE-287 (Improper Authentication). The core issue lies in the client’s failure to correctly validate the authenticity certificate by default during its network communications. This improper certificate validation allows an attacker with network access to perform a Man-in-the-Middle (MITM) attack. By intercepting and manipulating the communication between the Velneo vClient and its server, the attacker can potentially capture user credentials. The vulnerability does not require prior authentication (PR:N) but does require user interaction (UI:R), such as initiating a connection. The attack vector is 'Adjacent Network' (AV:A), meaning the attacker must be on the same or a logically adjacent network segment. The vulnerability impacts confidentiality severely (C:H), with limited impact on integrity (I:L) and no impact on availability (A:N). The CVSS 3.1 base score is 6.3, indicating a medium severity level. No known exploits in the wild have been reported, and no patches are explicitly linked in the provided information, suggesting that mitigation may require vendor updates or configuration changes. The vulnerability’s exploitation could lead to credential theft, enabling further unauthorized access or lateral movement within affected environments.

For European organizations using Velneo vClient 28.1.3, this vulnerability poses a significant risk to the confidentiality of user credentials, especially in environments where network segmentation is weak or where attackers can gain network access (e.g., corporate Wi-Fi, VPNs, or compromised internal networks). Credential compromise can lead to unauthorized access to sensitive business applications and data managed via Velneo platforms, potentially resulting in data breaches, intellectual property theft, or disruption of business processes. Given that Velneo is a development platform often used for business applications, the impact could extend to critical business operations. The requirement for user interaction and network proximity somewhat limits the attack surface but does not eliminate risk, particularly in hybrid or remote work environments where network controls may be less stringent. The absence of known exploits suggests limited active targeting but does not preclude opportunistic attacks, especially in sectors with high-value data or regulatory requirements such as finance, healthcare, and government within Europe.

1. Immediate mitigation should focus on network-level protections: enforce strict network segmentation and limit access to Velneo vClient servers to trusted network segments only. 2. Use VPNs or encrypted tunnels that enforce strong certificate validation independently of the client to mitigate MITM risks. 3. Educate users about the risks of connecting to untrusted networks and the importance of verifying connection prompts to reduce successful user interaction exploitation. 4. Monitor network traffic for unusual patterns indicative of MITM attempts or credential harvesting. 5. Engage with Velneo to obtain updates or patches that address certificate validation flaws; if unavailable, consider upgrading to newer versions or applying configuration changes that enforce strict certificate checks. 6. Implement multi-factor authentication (MFA) on Velneo platform access to reduce the impact of credential compromise. 7. Regularly audit and review client configurations and network security policies to ensure compliance with best practices.