CVE-2000-0345 is a vulnerability affecting multiple versions of Cisco IOS, specifically versions ranging from 9.14 up to 12.0t. The issue lies in the on-line help system options of Cisco routers, which allow non-privileged users—those without "enabled" mode access—to execute the "show" command and thereby obtain sensitive information. This vulnerability does not require authentication (Au:N) but does require local access (AV:L), meaning an attacker must have some form of access to the router's command-line interface, typically via console or telnet/SSH sessions that do not require elevated privileges. The vulnerability impacts confidentiality (C:P) but does not affect integrity or availability (I:N/A:N). The CVSS score is low (2.1), reflecting the limited impact and exploitation complexity. There is no patch available for this vulnerability, and no known exploits have been reported in the wild. The affected Cisco IOS versions are quite old, dating back to the late 1990s and early 2000s, which suggests that modern Cisco devices running updated IOS versions are not vulnerable. The vulnerability essentially allows an attacker with limited access to gather information that could potentially aid in further attacks or reconnaissance but does not allow direct control or disruption of the device.

For European organizations, the impact of this vulnerability is generally low due to its limited scope and the age of the affected IOS versions. However, organizations that still operate legacy Cisco routers running these outdated IOS versions could be at risk of information disclosure. Sensitive configuration details or network topology information exposed via the "show" commands could facilitate targeted attacks or lateral movement within the network. This is particularly relevant for critical infrastructure providers, telecommunications companies, and large enterprises that may have legacy equipment in their network infrastructure. The confidentiality breach could lead to increased risk of subsequent attacks, but since integrity and availability are not affected, the immediate operational impact is minimal. Given the absence of known exploits and the requirement for local access, the threat is primarily from insider threats or attackers who have already gained some foothold in the network.

Given that no patch is available for this vulnerability, mitigation should focus on compensating controls. First, organizations should identify and inventory all Cisco IOS devices and verify their software versions. Legacy devices running affected versions should be prioritized for upgrade to supported, patched IOS versions. If upgrading is not immediately feasible, restrict access to the router's command-line interface by enforcing strict access control policies, including limiting console, telnet, and SSH access to trusted administrators only. Implement network segmentation to isolate management interfaces from general user networks. Employ strong authentication mechanisms and consider using out-of-band management channels. Regularly audit user accounts and access logs to detect unauthorized access attempts. Additionally, disable or restrict the on-line help system options if possible, or configure the router to limit the information returned by "show" commands for non-privileged users. Finally, educate network administrators about the risks of using legacy equipment and the importance of timely updates and access controls.