CVE-2011-3759 in MyBB
Summary
by MITRE
MyBB (aka MyBulletinBoard) 1.6 allows remote attackers to obtain sensitive information via a direct request to a .php file, which reveals the installation path in an error message, as demonstrated by inc/3rdparty/diff/Diff/ThreeWay.php and certain other files.
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Analysis
by VulDB Data Team • 02/10/2019
The vulnerability identified as CVE-2011-3759 affects MyBB version 1.6, a popular open-source bulletin board system widely used for online community forums. This security flaw represents a classic information disclosure vulnerability that exposes sensitive system details to remote attackers. The issue manifests when users or attackers make direct requests to specific php files within the application's directory structure, particularly targeting files in the inc/3rdparty/diff/Diff/ThreeWay.php path and similar components. The vulnerability stems from the application's improper error handling mechanisms that fail to sanitize or suppress installation path information in error messages, thereby leaking critical system details to unauthorized parties.
The technical implementation of this vulnerability involves the application's failure to properly validate and sanitize input parameters when processing requests to php files. When a direct request is made to these specific files, the system generates error messages that inadvertently include the full server path where MyBB is installed. This occurs due to the lack of proper exception handling and error message sanitization within the application's codebase. The vulnerability is particularly concerning because it operates at the application level rather than requiring complex exploitation techniques, making it accessible to attackers with minimal technical expertise. The error messages contain path information that can be leveraged by threat actors to gain insights into the server environment, potentially enabling more sophisticated attacks.
From an operational impact perspective, this vulnerability creates significant risks for organizations running MyBB installations. The leaked installation paths can provide attackers with crucial information for planning subsequent attacks, including server structure details that may aid in identifying other potential vulnerabilities within the same system. The exposure of file paths can facilitate directory traversal attacks, privilege escalation attempts, and other exploitation techniques that rely on understanding the target system's layout. Additionally, this information disclosure can aid in fingerprinting the application version and identifying potential weaknesses in the system configuration. Organizations may face compliance violations and security audit failures due to this exposure, particularly in regulated environments where information disclosure is strictly prohibited.
The vulnerability aligns with CWE-200, which addresses information exposure, and demonstrates characteristics consistent with ATT&CK technique T1083, which covers system information discovery. Security professionals should note that this vulnerability represents a low-hanging fruit that can be exploited as part of reconnaissance activities. The remediation approach involves implementing proper error handling mechanisms that sanitize all error messages and prevent the disclosure of system paths. Organizations should update their MyBB installations to patched versions, implement input validation controls, and configure error reporting to prevent path information leakage. Additional mitigations include server-level configurations that suppress detailed error messages and regular security audits to identify similar vulnerabilities in other components of the application stack. The vulnerability underscores the importance of proper error handling practices and demonstrates how seemingly minor implementation flaws can create significant security risks in web applications.