CVE-2012-2326 in MyBB
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the Admin Control Panel (ACP) in MyBB (aka MyBulletinBoard) before 1.6.7 allows remote administrators to inject arbitrary web script or HTML via a malformed file name in an orphaned attachment.
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Analysis
by VulDB Data Team • 02/19/2019
The vulnerability CVE-2012-2326 represents a critical cross-site scripting flaw discovered in MyBB version 1.6.6 and earlier, specifically within the Admin Control Panel component. This issue affects the bulletin board system's handling of file names in orphaned attachment management, creating a pathway for remote attackers to execute malicious code through web scripts or HTML injection. The vulnerability is particularly concerning as it targets administrative interfaces, potentially allowing attackers to compromise entire forum installations through a single compromised administrator session.
The technical flaw stems from insufficient input validation and output sanitization within the ACP's orphaned attachment handling functionality. When administrators process orphaned attachments, the system fails to properly sanitize file names before displaying them in web interfaces, creating an XSS vector that can be exploited by remote attackers. This vulnerability is classified as CWE-79 - Improper Neutralization of Input During Web Page Generation, which specifically addresses the failure to properly escape or filter user-controllable data before including it in web responses. The flaw occurs during the rendering of attachment metadata where file names containing malicious scripts are directly embedded into HTML output without appropriate sanitization measures.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with potential access to administrative functions within the MyBB platform. Remote attackers who can influence the file names of orphaned attachments can inject malicious JavaScript code that executes in the context of other administrators' browsers. This creates a persistent threat vector where attackers can establish backdoors, steal session cookies, modify forum content, or escalate privileges to full administrative control. The vulnerability is particularly dangerous because it requires no authentication to exploit, as the malicious code executes during normal administrative operations when viewing orphaned attachments.
Security professionals should note this vulnerability's alignment with ATT&CK technique T1059.007 - Command and Scripting Interpreter: JavaScript, as it enables attackers to execute JavaScript code within victim browsers. The attack surface is further expanded by the fact that administrators frequently interact with attachment management features, making this vector highly exploitable in real-world scenarios. Organizations should implement immediate mitigations including updating to MyBB version 1.6.7 or later, which includes proper input sanitization for file names in orphaned attachment handling. Additional protective measures include implementing Content Security Policy headers, monitoring administrative interface access logs for suspicious file name patterns, and conducting regular security audits of attachment handling processes to prevent similar vulnerabilities from emerging in other components of the system.