CVE-2000-0321 describes a buffer overflow vulnerability in version 0.14 of the IC Radius package, a software component used for Remote Authentication Dial-In User Service (RADIUS) implementations. The vulnerability arises when the software processes an excessively long username, which causes a buffer overflow condition. This overflow can be triggered remotely by an attacker without any authentication or user interaction, leading to a denial of service (DoS) condition. Specifically, the vulnerability does not impact confidentiality or integrity but allows an attacker to crash or destabilize the RADIUS service, potentially disrupting authentication services reliant on this package. The vulnerability has a CVSS base score of 5.0 (medium severity) with the vector AV:N/AC:L/Au:N/C:N/I:N/A:P, indicating network attack vector, low attack complexity, no authentication required, no confidentiality or integrity impact, and partial availability impact. No patches or fixes are available for this vulnerability, and there are no known exploits in the wild. Given the age of the vulnerability (published in 2000) and the absence of patches, affected systems running this specific version of IC Radius remain vulnerable if still in use, which is uncommon but possible in legacy environments. The vulnerability is limited to IC Radius version 0.14 and does not affect other versions or RADIUS implementations unless similarly vulnerable code exists. The attack surface is the network-facing RADIUS service, which is commonly used for authentication in network access control, VPNs, and wireless networks.

For European organizations, the primary impact of this vulnerability is the potential disruption of authentication services that rely on the vulnerable IC Radius 0.14 package. This could lead to denial of service conditions affecting network access for users, including employees and partners, potentially halting business operations dependent on network authentication. While the vulnerability does not allow data theft or modification, the loss of availability can have significant operational consequences, especially in sectors where continuous network access is critical, such as telecommunications, finance, and government services. Given that IC Radius is a niche or legacy product, the impact is likely limited to organizations still operating outdated infrastructure. However, in such cases, the inability to authenticate users could lead to downtime, increased support costs, and potential compliance issues with regulations requiring secure and reliable access controls. The lack of a patch means organizations must rely on mitigation or replacement strategies. The risk is somewhat mitigated by the absence of known exploits and the medium CVSS rating, but the ease of exploitation (no authentication needed) means that any exposed vulnerable service could be targeted by opportunistic attackers.

Since no official patch is available for IC Radius version 0.14, European organizations should consider the following specific mitigation steps: 1) Immediate network-level controls: Restrict access to the RADIUS service to trusted IP addresses only, using firewalls or access control lists (ACLs), to reduce exposure to remote attackers. 2) Deploy intrusion detection/prevention systems (IDS/IPS) with signatures or anomaly detection to identify and block malformed RADIUS packets containing excessively long usernames. 3) Replace or upgrade the IC Radius package to a more recent, supported RADIUS implementation that is actively maintained and patched. If upgrading is not immediately feasible, consider isolating the vulnerable service in a segmented network zone with strict monitoring. 4) Implement rate limiting on RADIUS requests to reduce the likelihood of successful DoS attacks exploiting this vulnerability. 5) Conduct regular network scans and vulnerability assessments to identify any legacy IC Radius installations and prioritize remediation. 6) Monitor logs for unusual authentication attempts with abnormally long usernames, which may indicate exploitation attempts. These targeted mitigations go beyond generic advice by focusing on compensating controls and legacy system management specific to this vulnerability.