The vulnerability identified as CVE-2025-25613 affects the FS Inc S3150-8T2F 8-Port Gigabit Ethernet L2+ Switch, specifically all firmware versions before 2.2.0D Build 135103. The core issue lies in the web-based administrative interface's handling of authentication cookies. These cookies, which contain usernames and passwords, are transmitted during every POST request to the server. Instead of using secure encryption or at least secure transport mechanisms, the credentials are only base64 encoded, which is a reversible encoding scheme and not a form of encryption. This means that anyone with access to the network traffic can easily decode these cookies and retrieve administrative credentials. The vulnerability compromises confidentiality and integrity by exposing sensitive authentication data, potentially allowing attackers to gain unauthorized administrative access to the switch. Such access could lead to network manipulation, interception, or denial of service. No known public exploits have been reported yet, but the vulnerability is critical due to the sensitive nature of the data exposed and the lack of authentication or user interaction barriers for exploitation. The vulnerability affects network devices commonly deployed in enterprise and service provider environments, making it a significant risk for organizations relying on these switches for network management. The lack of a CVSS score requires an assessment based on the impact and exploitability factors.

For European organizations, this vulnerability poses a serious risk to network security and operational integrity. The exposure of administrative credentials in cleartext allows attackers with network access—such as insiders, compromised devices on the same LAN, or attackers who have gained a foothold in the network—to intercept credentials and take control of network switches. This can lead to unauthorized configuration changes, traffic interception, network segmentation bypass, or complete denial of service. Critical infrastructure operators, financial institutions, and large enterprises that rely on FS Inc switches for their network backbone are particularly vulnerable. The breach of confidentiality and integrity could result in data leaks, disruption of services, and significant financial and reputational damage. Additionally, the lack of encryption in management traffic violates best practices and regulatory requirements such as GDPR, which mandates protection of sensitive data in transit. The threat is amplified in environments where network segmentation is weak or where remote management interfaces are exposed without additional security controls.

1. Immediate upgrade of all affected FS Inc S3150-8T2F switches to firmware version 2.2.0D Build 135103 or later, where this vulnerability is addressed. 2. Implement network segmentation to isolate management interfaces from general user traffic, limiting exposure to trusted administrators only. 3. Enforce the use of secure management protocols such as HTTPS with valid certificates, SSH, or VPN tunnels for remote access to network devices. 4. Regularly audit network traffic for unencrypted credentials or suspicious activity using intrusion detection systems (IDS) and network monitoring tools. 5. Apply strict access control policies and multi-factor authentication (MFA) for administrative access where supported. 6. Educate network administrators on the risks of transmitting credentials in cleartext and the importance of secure configuration. 7. Maintain an inventory of network devices and firmware versions to ensure timely patch management and vulnerability remediation. 8. Consider deploying network anomaly detection solutions to identify unusual administrative access patterns that could indicate exploitation attempts.