CVE-1999-0632 refers to the presence of the RPC (Remote Procedure Call) portmapper service running on a system. The portmapper service is a legacy network service that maps RPC program numbers to network port numbers, enabling RPC clients to locate the appropriate service ports on a server. While the CVE itself does not describe a direct vulnerability or exploit, the running of the portmapper service can be considered a security risk because it can provide attackers with information about RPC services available on the host. This information can be leveraged for reconnaissance to identify potential attack vectors. The portmapper service listens on TCP and UDP port 111 and is known to be targeted for various RPC-based attacks, including denial of service or exploitation of vulnerable RPC services. However, the CVE entry indicates no direct impact on confidentiality, integrity, or availability, and no authentication or user interaction is required to detect the service. The CVSS vector AV:N/AC:L/Au:N/C:N/I:N/A:N reflects that the service is network accessible, requires low attack complexity, no authentication, but does not directly impact system security properties. No patches are available because this is a service presence issue rather than a software flaw. The main security concern is that the exposed portmapper service can aid attackers in mapping the network and identifying RPC services that may have vulnerabilities. Therefore, the risk is indirect and depends on the presence of other vulnerable RPC services on the host.

For European organizations, the presence of an exposed RPC portmapper service can increase the attack surface by revealing RPC services that might be vulnerable to exploitation. While the portmapper itself does not directly compromise confidentiality, integrity, or availability, it facilitates reconnaissance activities that can lead to targeted attacks. Organizations with legacy systems or those running older UNIX/Linux servers that rely on RPC services are particularly at risk. Attackers can use the portmapper to identify services such as NFS, NIS, or other RPC-based applications, which have historically had vulnerabilities. This can lead to unauthorized access, data leakage, or denial of service if those services are exploited. In critical infrastructure sectors or industries with high-value data in Europe, such reconnaissance can be a precursor to more severe attacks. Additionally, compliance with European data protection regulations (e.g., GDPR) may be impacted if an attacker leverages this information to breach systems and access personal data.

To mitigate risks associated with the RPC portmapper service, European organizations should: 1) Disable the portmapper service on systems where RPC is not required. 2) Restrict network access to port 111 using firewalls or network segmentation, allowing only trusted hosts to communicate with RPC services. 3) Employ host-based access controls to limit which users or processes can interact with RPC services. 4) Regularly audit and inventory RPC services running on the network to identify and remediate legacy or unnecessary services. 5) Consider migrating legacy RPC-dependent applications to more secure alternatives or updated versions that do not rely on portmapper. 6) Monitor network traffic for unusual RPC activity that could indicate reconnaissance or exploitation attempts. 7) Implement intrusion detection/prevention systems (IDS/IPS) with signatures for RPC-related attacks. These steps go beyond generic advice by focusing on minimizing exposure, controlling access, and actively monitoring RPC-related network activity.