CVE-2015-4552 in MyBB
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the quick edit function in xmlhttp.php in MyBB (aka MyBulletinBoard) before 1.8.5 allows remote attackers to inject arbitrary web script or HTML via the content of a post.
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Analysis
by VulDB Data Team • 11/24/2024
The CVE-2015-4552 vulnerability represents a critical cross-site scripting flaw discovered in MyBB versions prior to 1.8.5, specifically within the quick edit functionality of the xmlhttp.php script. This vulnerability resides in the web application's handling of user input during post editing operations, creating a significant security risk for forum administrators and users who rely on the MyBB platform for community discussions and content management. The flaw stems from inadequate input validation and output sanitization mechanisms that fail to properly escape or filter malicious content submitted through the quick edit interface.
The technical exploitation of this vulnerability occurs when remote attackers leverage the xmlhttp.php endpoint to inject malicious scripts or HTML content into forum posts through the quick edit function. This allows attackers to execute arbitrary web scripts in the context of other users' browsers, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of victims. The vulnerability manifests because the application does not adequately sanitize user-supplied content before rendering it back to other users, creating an environment where malicious payloads can persist and execute in legitimate user sessions.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable sophisticated attacks such as cookie theft, session manipulation, and the potential for privilege escalation within the forum environment. Attackers can craft malicious posts that, when viewed by other users, execute scripts that steal session cookies or redirect users to malicious sites. This vulnerability directly violates security principles outlined in CWE-79, which addresses cross-site scripting flaws, and can be categorized under ATT&CK technique T1566 for initial access through malicious content. The widespread use of MyBB in community forums and discussion platforms amplifies the potential damage, as a single compromised forum can serve as a vector for attacks against multiple users.
Mitigation strategies for CVE-2015-4552 require immediate application of the official patch released by MyBB developers for versions 1.8.5 and later, which implements proper input sanitization and output encoding for all user-generated content. Organizations should also implement additional defensive measures including content security policies, regular security audits of forum components, and monitoring for suspicious activity patterns. Network-level protections such as web application firewalls can provide additional layers of defense, though the primary remediation must focus on updating the core application. Security teams should conduct comprehensive vulnerability assessments to identify any other potential XSS vectors within the forum platform and ensure that all user input is properly validated and escaped before processing. The vulnerability highlights the critical importance of maintaining up-to-date software versions and implementing robust input validation mechanisms as recommended by industry standards including OWASP Top Ten and NIST cybersecurity guidelines.