CVE-1999-0106 is a vulnerability related to the finger protocol, specifically involving finger redirection that allows what is termed as 'finger bombs.' The finger protocol is an old network protocol used to retrieve information about users on a remote system. The vulnerability arises when the finger service allows redirection of finger requests, which can be exploited to cause denial of service (DoS) conditions by overwhelming the target system with excessive or malformed finger requests, effectively creating a 'finger bomb.' This does not compromise confidentiality or integrity but impacts availability by potentially crashing or severely degrading the finger service or the host system. The vulnerability requires local access (AV:L - Attack Vector: Local) and no authentication (Au:N), with low attack complexity (AC:L). The CVSS score is 2.1, indicating a low severity primarily due to the limited impact and the requirement for local access. There are no known patches or exploits in the wild, and the affected versions are unspecified, reflecting the age and obsolescence of the finger protocol in modern environments.

For European organizations, the impact of this vulnerability is minimal in modern contexts because the finger protocol is largely deprecated and rarely enabled on contemporary systems. However, legacy systems or specialized environments that still run finger services could be susceptible to denial of service attacks that disrupt user information services or potentially affect system stability. This could lead to minor operational disruptions, particularly in organizations with legacy infrastructure or in academic and research institutions where finger might still be in use. The vulnerability does not expose sensitive data or allow unauthorized access, so the risk to confidentiality and integrity is negligible. Availability impact is limited to the finger service or the host system's stability under attack conditions.

Given the obsolescence of the finger protocol, the primary mitigation is to disable the finger service entirely on all systems, especially those connected to networks. For environments where finger must remain enabled, implement strict access controls to limit finger service usage to trusted local users only. Network-level filtering can be applied to block finger protocol traffic (typically TCP port 79) from untrusted sources. Monitoring and logging finger service usage can help detect unusual activity indicative of attempted finger bomb attacks. Since no patches are available, these configuration and network controls are the most effective mitigations. Additionally, organizations should review and update legacy systems to modern protocols and services to reduce exposure to such outdated vulnerabilities.