CVE-1999-1420 identifies a critical vulnerability in NBase network switches models NH2012, NH2012R, NH2015, and NH2048. These switches contain a hardcoded backdoor password that cannot be disabled or removed by administrators. This backdoor allows remote attackers to gain unauthorized access to the switch's management interface without any authentication. Once accessed, attackers can fully modify the switch's configuration, potentially altering network traffic flows, disabling security controls, or creating persistent network access points. The vulnerability affects multiple firmware versions (1.33, 2.1, 2.51, 2.53) and has been assigned a maximum CVSS score of 10.0, reflecting its critical impact and ease of exploitation. The attack vector is network-based (AV:N), requires no authentication (Au:N), and has low attack complexity (AC:L). The vulnerability compromises confidentiality, integrity, and availability (C:C/I:C/A:C) of the affected devices. No patches or vendor fixes are available, and while no known exploits have been reported in the wild, the presence of an unremovable backdoor password represents a severe security risk. Given the age of the vulnerability (published in 1998), affected devices are likely legacy equipment still in use in some environments, which may pose ongoing risks if not replaced or isolated.

For European organizations, the presence of this vulnerability in network infrastructure devices can lead to severe consequences. Compromised switches can allow attackers to intercept sensitive communications, manipulate network configurations to bypass security controls, or launch further attacks within the internal network. This can result in data breaches, disruption of critical services, and loss of trust. Industries with high reliance on stable and secure network infrastructure, such as finance, healthcare, telecommunications, and government, are particularly at risk. Additionally, the inability to patch or disable the backdoor means organizations must rely on compensating controls or device replacement, which can be costly and operationally challenging. The vulnerability also raises compliance concerns under regulations like GDPR, where unauthorized access and data breaches must be prevented and reported.

Since no patches or vendor fixes exist for this vulnerability, European organizations should prioritize the following specific mitigation steps: 1) Identify and inventory all NBase NH2012, NH2012R, NH2015, and NH2048 switches in their networks, including firmware versions. 2) Immediately isolate these devices from critical network segments or the internet to reduce exposure. 3) Replace affected switches with modern, supported hardware that does not contain known backdoors. 4) Implement strict network segmentation and access controls to limit management interface exposure. 5) Monitor network traffic for unusual activity indicative of unauthorized access or configuration changes. 6) Employ network intrusion detection/prevention systems (IDS/IPS) to detect exploitation attempts. 7) Enforce strong physical security to prevent local access to devices. 8) Review and update incident response plans to address potential exploitation scenarios involving legacy network equipment.