CVE-2000-0395 is a buffer overflow vulnerability identified in CProxy version 3.3sp2, a proxy server product developed by Computalynx. The vulnerability arises when the server processes an excessively long HTTP request, which causes a buffer overflow condition. This overflow can be triggered remotely by an unauthenticated attacker sending a specially crafted HTTP request to the affected server. The consequence of this vulnerability is a denial of service (DoS) condition, where the server may crash or become unresponsive, disrupting normal proxy operations. Notably, this vulnerability does not impact confidentiality or integrity, as it does not allow code execution or data manipulation, but solely affects availability. The vulnerability has a CVSS v2 base score of 5.0, indicating a medium severity level, with the vector AV:N/AC:L/Au:N/C:N/I:N/A:P, meaning it is remotely exploitable over the network, requires no authentication, has low attack complexity, and impacts only availability. There is no patch available for this vulnerability, and no known exploits have been reported in the wild. Given the age of the vulnerability (published in 2000) and the lack of patch or exploit activity, it is likely that the affected product is either obsolete or minimally used in modern environments. However, any legacy systems still running CProxy 3.3sp2 remain vulnerable to remote DoS attacks via long HTTP requests.

For European organizations, the primary impact of this vulnerability is the potential disruption of proxy services that rely on CProxy 3.3sp2. Proxy servers often serve as critical components in network infrastructure, providing caching, filtering, and security functions. A successful DoS attack could lead to temporary loss of internet access or degraded network performance for users behind the proxy, impacting business continuity and productivity. While the vulnerability does not allow data breaches or system compromise, the availability impact could be significant in environments where proxy uptime is critical, such as financial institutions, government agencies, or large enterprises. Additionally, organizations with legacy systems or those that have not updated their proxy infrastructure may be more susceptible. Given the lack of patch and exploit activity, the risk is mitigated by the rarity of the product in current use, but any remaining deployments in Europe should be considered at risk for service disruption.

Since no official patch is available for CProxy 3.3sp2, European organizations should consider the following specific mitigation strategies: 1) Immediate identification and inventory of any systems running CProxy 3.3sp2 to assess exposure. 2) If feasible, replace or upgrade the proxy server to a modern, supported product that receives security updates and patches. 3) Implement network-level protections such as Web Application Firewalls (WAFs) or Intrusion Prevention Systems (IPS) configured to detect and block abnormally long HTTP requests targeting proxy servers. 4) Apply rate limiting and request size restrictions on HTTP traffic entering the proxy to prevent buffer overflow attempts. 5) Employ network segmentation to isolate legacy proxy servers from critical infrastructure and sensitive data stores, limiting the blast radius of potential DoS attacks. 6) Monitor proxy server logs and network traffic for unusual patterns indicative of attempted exploitation. 7) Develop and test incident response plans specifically addressing proxy service outages to minimize operational impact. These targeted mitigations go beyond generic advice by focusing on compensating controls and proactive detection tailored to the nature of this vulnerability and the lack of a patch.