CVE-1999-0640 identifies the presence of the Gopher service running on a system as a security vulnerability. The Gopher protocol, developed in the early 1990s, is a TCP/IP application layer protocol designed for distributed document search and retrieval. Although largely obsolete today, the Gopher service can still be found running on legacy systems or misconfigured servers. The vulnerability itself is not a flaw in the protocol or software per se, but rather the fact that having the Gopher service active exposes the system to significant risk. According to the CVSS v2 score of 10.0 (AV:N/AC:L/Au:N/C:C/I:C/A:C), this vulnerability is remotely exploitable over the network without authentication, with low attack complexity, and can lead to complete compromise of confidentiality, integrity, and availability. Attackers can leverage the Gopher service to access sensitive data, modify or delete information, or disrupt service availability. Since no patches are available and no specific affected versions are listed, the risk arises from the mere presence of the service. The lack of known exploits in the wild suggests limited active targeting, but the theoretical risk remains critical due to the service's inherent insecurity and potential for abuse. This vulnerability is primarily a legacy risk, relevant to organizations that still run or expose Gopher services, often due to outdated infrastructure or insufficient hardening practices.

For European organizations, the impact of this vulnerability can be significant if legacy systems running the Gopher service are present and accessible from untrusted networks. Confidential information could be exposed, including internal documents or sensitive data indexed by the Gopher service. Integrity risks include unauthorized modification or deletion of data accessible via Gopher, potentially affecting business operations or compliance with data protection regulations such as GDPR. Availability could be compromised through denial-of-service attacks exploiting the service. While modern networks rarely use Gopher, certain sectors with legacy infrastructure—such as government agencies, educational institutions, or industrial control systems—may be at higher risk. The presence of this vulnerability could also be leveraged as a foothold for lateral movement within networks, increasing the overall threat landscape. Additionally, exposure of this service could lead to reputational damage and regulatory penalties if exploited to leak personal or sensitive data.

The primary mitigation is to identify and disable the Gopher service on all systems within the organization. Network scanning tools should be used to detect any active Gopher servers. Systems running legacy software that includes Gopher should be upgraded or isolated from external networks. If disabling the service is not immediately possible, strict firewall rules should block incoming and outgoing traffic on the default Gopher port (TCP 70). Network segmentation and access controls should be enforced to limit exposure. Regular vulnerability assessments and audits should include checks for legacy services like Gopher. Since no patches exist, removing or isolating the service is the only effective remediation. Additionally, organizations should review and update their asset inventories to identify legacy systems and plan for their decommissioning or modernization. Monitoring network traffic for unusual Gopher protocol activity can help detect attempted exploitation.