CVE-2000-0426 is a vulnerability affecting UltraBoard version 1.6 and other versions of this bulletin board software developed by UltraScripts. The issue arises when remote attackers send requests that include the string "UltraBoard" in the Session parameter. This triggers the software to fork multiple copies of itself, leading to resource exhaustion on the hosting server. The vulnerability results in a denial of service (DoS) condition by overwhelming the system's processing capabilities and potentially causing the application or the entire server to become unresponsive. The attack vector is network-based, requiring no authentication or user interaction, and can be executed remotely by simply crafting malicious HTTP requests. The CVSS score assigned is 5.0 (medium severity), reflecting that while the vulnerability does not impact confidentiality or integrity, it significantly affects availability. No patches or fixes are currently available for this vulnerability, and there are no known exploits in the wild documented at this time. The root cause is related to improper handling of session parameters, allowing an attacker to manipulate the application’s process management behavior to cause excessive forking.

For European organizations using UltraBoard 1.6 or similar vulnerable versions, this vulnerability poses a risk primarily to service availability. Organizations relying on UltraBoard for community forums, customer support, or internal communications could experience service outages, disrupting business operations and user engagement. Although the vulnerability does not compromise data confidentiality or integrity, the denial of service could lead to reputational damage, loss of user trust, and potential financial impacts due to downtime. Given the age of the software and the lack of patches, organizations may also face challenges in maintaining compliance with security standards if vulnerable systems remain operational. The impact is more pronounced for organizations with high traffic forums or critical dependency on UltraBoard-hosted services, especially if no mitigations are in place to detect or block malicious session parameter manipulations.

Since no official patches are available, European organizations should implement compensating controls to mitigate the risk. These include: 1) Deploying Web Application Firewalls (WAFs) with custom rules to detect and block requests containing suspicious Session parameter values such as the string "UltraBoard". 2) Limiting the number of concurrent processes or forks that the UltraBoard application can spawn at the operating system level to prevent resource exhaustion. 3) Implementing network-level rate limiting and IP reputation filtering to reduce the likelihood of automated or repeated attack attempts. 4) Monitoring server logs and application behavior for unusual spikes in process creation or session parameter anomalies to enable early detection. 5) Considering migration to more modern, actively maintained forum software to eliminate reliance on vulnerable legacy systems. 6) Isolating UltraBoard servers in segmented network zones to minimize the impact of potential DoS attacks on broader infrastructure.