CVE-2004-0091 in vBulletin
Summary
by MITRE
** DISPUTED ** NOTE: this issue has been disputed by the vendor. Cross-site scripting (XSS) vulnerability in register.php for unknown versions of vBulletin allows remote attackers to inject arbitrary HTML or web script via the reg_site (or possibly regsite) parameter. NOTE: the vendor has disputed this issue, saying "There is no hidden field called reg_site , nor any $reg_site variable anywhere in the vBulletin 2 or vBulletin 3 source code or templates, nor has it ever existed. We can only assume that this vulnerability was found in a site running code modified from that supplied by Jelsoft."
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Analysis
by VulDB Data Team • 08/08/2024
The vulnerability described in CVE-2004-0091 represents a disputed cross-site scripting issue within the vBulletin forum software ecosystem. This particular CVE has been officially disputed by the vBulletin vendor, who has firmly stated that no such hidden field or variable named reg_site exists within the legitimate vBulletin 2 or vBulletin 3 source code or templates. The vendor's position indicates that any detection of such vulnerabilities would have originated from modified codebases rather than the official software distribution, suggesting that the reported issue stems from third-party modifications or custom implementations that deviate from the original Jelsoft codebase.
The technical nature of this vulnerability, if it were to exist, would have constituted a classic cross-site scripting flaw that allows remote attackers to inject malicious HTML or web scripts into the vulnerable application. The reg_site parameter mentioned in the description would have served as a potential injection vector for attackers to execute arbitrary code within the context of users' browsers. This type of vulnerability falls under the CWE-79 category of Cross-site Scripting, which represents one of the most prevalent and dangerous web application security flaws. The vulnerability could have enabled attackers to perform session hijacking, deface websites, steal user credentials, or redirect users to malicious sites.
From an operational impact perspective, if this vulnerability had been legitimate, it would have posed significant risks to vBulletin installations, particularly those that were improperly configured or had been modified from the original source code. The attack surface would have been particularly concerning for forums that relied on user registration functionality, as attackers could have exploited this weakness to compromise user sessions and potentially gain unauthorized access to administrative functions. The impact would have been amplified in environments where users trusted the forum platform and engaged in sensitive activities such as posting personal information or accessing private content.
The vendor's dispute of this CVE highlights the importance of proper code auditing and the distinction between legitimate software vulnerabilities and issues arising from custom modifications. The attribution to Jelsoft modifications suggests that organizations running vBulletin installations should carefully review their codebase for unauthorized changes and maintain proper version control practices. This case demonstrates how third-party modifications or custom implementations can introduce security flaws that differ from the vendor's official software, making it crucial for organizations to conduct thorough security assessments of their modified code. The incident underscores the necessity of adhering to secure coding practices and maintaining official software versions to avoid introducing vulnerabilities that could be exploited by threat actors.
Security practitioners should note that while this specific CVE has been disputed, it serves as a reminder of the importance of validating reported vulnerabilities against official source code and maintaining awareness of potential security flaws in modified software. The ATT&CK framework would categorize this type of vulnerability under the T1190 technique of Exploit Public-Facing Application, as it represents an attack vector targeting web applications accessible to remote users. Organizations should implement proper input validation and output encoding mechanisms to prevent XSS attacks, regardless of whether the specific vulnerability described in this CVE is present in their systems.