CVE-2000-0063 is a vulnerability found in the cgiproc CGI script of the Nortel Contivity HTTP server version 1.0. This vulnerability allows remote attackers to read arbitrary files on the affected server by specifying the filename as a parameter to the cgiproc script. The vulnerability arises because the CGI script does not properly validate or sanitize user input, enabling attackers to traverse directories and access sensitive files outside the intended directory scope. The vulnerability has a CVSS v2 base score of 5.0, indicating a medium severity level. The attack vector is network-based (AV:N), requires no authentication (Au:N), and has low attack complexity (AC:L). The impact is limited to confidentiality (C:P), with no impact on integrity (I:N) or availability (A:N). There is no patch available for this vulnerability, and no known exploits have been reported in the wild. The affected product, Nortel Contivity, is a VPN and remote access solution that was widely used in enterprise environments around the time of the vulnerability's publication in 2000. Given the age of the vulnerability and product, active exploitation today is unlikely, but legacy systems may still be at risk if unpatched and exposed.

For European organizations, the primary impact of this vulnerability is unauthorized disclosure of sensitive information. Attackers exploiting this flaw can read arbitrary files, potentially gaining access to configuration files, credentials, or other confidential data stored on the Nortel Contivity HTTP server. This can lead to further compromise of the network or facilitate lateral movement. Although the vulnerability does not allow modification or disruption of services, the confidentiality breach can have serious consequences, especially for organizations handling sensitive personal data under GDPR regulations. The lack of a patch means organizations must rely on compensating controls or system upgrades. The risk is higher for organizations still operating legacy Nortel Contivity devices exposed to untrusted networks, including remote access points. Given the medium severity and no known active exploits, the immediate risk is moderate but should not be ignored in environments where the product is still in use.

Since no patch is available for this vulnerability, European organizations should take specific steps to mitigate the risk: 1) Identify and inventory all Nortel Contivity devices in the environment, especially those running version 1.0 of the HTTP server. 2) Isolate vulnerable devices from untrusted networks by placing them behind firewalls or VPNs that restrict access to trusted users only. 3) Disable or restrict access to the cgiproc CGI script if possible, or configure the HTTP server to deny requests with suspicious parameters. 4) Monitor network traffic and logs for unusual file access patterns or attempts to exploit CGI scripts. 5) Plan for replacement or upgrade of legacy Nortel Contivity devices with modern, supported VPN solutions that do not have known vulnerabilities. 6) Implement strict access controls and network segmentation to limit the impact of any potential compromise. 7) Educate IT staff about the risks associated with legacy systems and the importance of timely decommissioning.