CVE-2005-2438 in UseBB
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in UseBB 0.5.1 and earlier allows remote attackers to inject arbitrary Javascript via the BBCode color value.
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Analysis
by VulDB Data Team • 07/27/2017
The vulnerability described in CVE-2005-2438 represents a classic cross-site scripting flaw affecting UseBB version 0.5.1 and earlier. This security weakness resides in the forum software's handling of BBCode color parameters, specifically when processing user input for color formatting within posts. The vulnerability enables remote attackers to execute malicious javascript code within the context of other users' browsers, creating a significant risk for forum communities that rely on user-generated content. The flaw demonstrates poor input validation and output encoding practices that are fundamental to preventing XSS attacks in web applications.
The technical implementation of this vulnerability stems from the application's failure to properly sanitize or escape user-supplied color values in BBCode tags. When users create posts containing BBCode with color parameters such as [color=javascript:alert(1)]text[/color], the application processes these values without adequate validation, allowing malicious code to persist in the rendered HTML output. This specific weakness falls under CWE-79 which defines improper neutralization of input during web page generation, a core principle that governs XSS vulnerability classification. The vulnerability operates by bypassing the application's intended input filtering mechanisms, allowing attacker-controlled data to be interpreted as executable script rather than plain text.
The operational impact of this vulnerability extends beyond simple script execution, creating potential for more sophisticated attacks within the forum environment. An attacker could leverage this flaw to steal session cookies, redirect users to malicious sites, deface forum content, or establish persistent malicious presence within the community. The remote nature of the attack means that exploitation does not require local access or special privileges, making it particularly dangerous for public-facing forum platforms where users may have varying levels of trust. This vulnerability directly aligns with ATT&CK technique T1531 which focuses on use of malicious links or content to compromise user systems, and represents a common vector for credential theft and social engineering attacks in web applications.
Mitigation strategies for this vulnerability require immediate implementation of proper input sanitization and output encoding measures. The most effective approach involves validating all user-supplied color values against a strict whitelist of acceptable color formats, rejecting any input containing javascript protocols or suspicious character sequences. Additionally, implementing proper HTML escaping for all dynamic content ensures that even if malicious input slips through validation, it cannot be executed as script code. Organizations should also consider implementing content security policies to further restrict script execution capabilities within forum environments. The fix for this specific vulnerability requires updating to UseBB version 0.5.2 or later, which includes proper input validation for BBCode color parameters, demonstrating the importance of keeping web applications updated against known security flaws.