CVE-2006-4157 in YaBB
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in index.php in Yet another Bulletin Board (YaBB) allows remote attackers to inject arbitrary web script or HTML via the categories parameter.
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Analysis
by VulDB Data Team • 08/02/2018
The vulnerability identified as CVE-2006-4157 represents a classic cross-site scripting flaw within the Yet another Bulletin Board (YaBB) software ecosystem. This issue specifically targets the index.php script and manifests through improper input validation of the categories parameter, creating a pathway for malicious actors to execute arbitrary web scripts or HTML code within the context of affected user sessions. The vulnerability falls under the broader category of CWE-79 - Improper Neutralization of Input During Web Page Generation, which is a fundamental weakness in web application security architecture.
The technical implementation of this XSS vulnerability occurs when the YaBB application fails to properly sanitize or escape user-supplied input from the categories parameter before incorporating it into dynamically generated web pages. This allows attackers to inject malicious payloads that are then executed by unsuspecting users who view the affected pages. The flaw exists at the application layer where input validation mechanisms are insufficient to prevent the injection of potentially harmful script code, making it particularly dangerous in bulletin board environments where user-generated content is common and trusted.
From an operational perspective, this vulnerability poses significant risks to both user privacy and system integrity within YaBB installations. Attackers can leverage this flaw to steal session cookies, redirect users to malicious sites, deface bulletin board content, or perform other malicious activities that compromise the security of the entire platform. The impact extends beyond individual user accounts to potentially affect the entire community forum, as the injected scripts can persist and affect multiple users who visit the compromised pages. This vulnerability directly aligns with ATT&CK technique T1531 - Account Access Removal, as it can be used to hijack user sessions and potentially escalate privileges through session manipulation.
The exploitation of this vulnerability requires minimal technical skill and can be accomplished through simple web requests that include malicious script payloads in the categories parameter. The attack surface is particularly broad given that bulletin boards typically serve as community platforms where users frequently interact with content, making the potential for widespread impact substantial. Organizations running YaBB systems would be vulnerable to various attack vectors including credential theft, data manipulation, and reputation damage. The vulnerability demonstrates a critical gap in input validation practices and highlights the importance of implementing robust sanitization mechanisms for all user-supplied data in web applications.
Mitigation strategies for CVE-2006-4157 should focus on immediate input validation and output encoding measures. The most effective approach involves implementing strict sanitization of all user input, particularly parameters like categories, through proper escaping techniques before any content is rendered in web pages. Organizations should also implement Content Security Policy headers to limit script execution capabilities and consider input length restrictions to prevent overly complex injection attempts. Additionally, regular security audits and vulnerability assessments should be conducted to identify similar weaknesses in legacy web applications. The remediation process should include updating to patched versions of YaBB software, implementing proper web application firewall rules, and establishing comprehensive monitoring for suspicious parameter usage patterns. This vulnerability serves as a critical reminder of the importance of secure coding practices and the necessity of regular security updates in maintaining web application integrity against persistent threats.