CVE-1999-0105 is a vulnerability in the 'finger' service, a network utility historically used to retrieve information about users on remote systems. The vulnerability arises from the way the finger daemon processes input containing a long string of '@' symbols, which allows recursive searches. Specifically, by crafting a query with multiple '@' characters, an attacker can cause the finger service to recursively query other hosts, potentially leading to resource exhaustion or denial of service conditions. This behavior can result in the finger daemon entering an infinite loop or excessive network traffic generation, impacting system availability. The vulnerability does not affect confidentiality or integrity directly, as it does not allow unauthorized data access or modification. It requires local access (AV:L) and no authentication (Au:N), but the attack complexity is low (AC:L). Given the age of this vulnerability (published in 1997) and the obsolescence of the finger service in modern environments, it is rarely encountered in contemporary systems. No patches are available, and no known exploits are reported in the wild.

For European organizations, the impact of CVE-1999-0105 is generally minimal due to the finger service's obsolescence and limited use in modern IT infrastructures. However, legacy systems or specialized environments that still run finger daemons could be susceptible to denial of service attacks, potentially disrupting user information services or related network operations. The vulnerability primarily affects availability, which could lead to minor operational interruptions. Confidentiality and integrity remain unaffected. Organizations relying on legacy UNIX or BSD systems, particularly in academic or research institutions where finger might still be in use, should be aware of this risk. The low CVSS score (2.1) and absence of known exploits further reduce the threat level in typical enterprise environments.

Given that no patches are available, the most effective mitigation is to disable the finger service entirely if it is not required. For systems where finger is necessary, restrict access to the service using firewall rules or TCP wrappers to limit queries to trusted hosts only. Monitoring network traffic for unusual finger queries containing multiple '@' symbols can help detect attempted exploitation. Additionally, consider replacing finger with more secure and modern user information services or protocols. Regularly audit systems to identify and decommission legacy services like finger to reduce the attack surface. Employ network segmentation to isolate legacy systems from critical infrastructure to minimize potential impact.