CVE-2015-8977 in MyBB
Summary
by MITRE
MyBB (aka MyBulletinBoard) before 1.6.18 and 1.8.x before 1.8.6 and MyBB Merge System before 1.8.6 allows remote attackers to obtain the installation path via vectors involving error log files.
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Analysis
by VulDB Data Team • 08/08/2020
The vulnerability identified as CVE-2015-8977 affects MyBB bulletin board systems and the MyBB Merge System across multiple versions including pre-1.6.18 and pre-1.8.6 releases. This issue represents a critical information disclosure vulnerability that exposes installation paths through improper error handling mechanisms. The flaw resides in how the system manages error log files, creating an unintended information leakage channel that could be exploited by remote attackers to gain knowledge about the underlying system configuration.
This vulnerability operates through specific attack vectors that involve manipulation of error log files within the MyBB framework. When the system encounters errors during operation, it generates log entries that inadvertently contain sensitive path information. The flaw occurs because the error handling routines do not properly sanitize or restrict the information contained in these logs, allowing attackers to access the complete installation path through carefully crafted requests that trigger specific error conditions. This represents a classic path traversal and information disclosure weakness that can be classified under CWE-200, which deals with information exposure.
The operational impact of CVE-2015-8977 extends beyond simple path disclosure, as the leaked installation paths can serve as foundational information for more sophisticated attacks. Attackers can leverage this information to perform targeted exploitation attempts, including directory traversal attacks, file inclusion vulnerabilities, or system enumeration techniques. The exposure of installation paths enables adversaries to better understand the system architecture and potentially identify additional vulnerabilities that may exist within the same environment. This vulnerability aligns with ATT&CK technique T1083, which covers directory and file system discovery, and can facilitate further reconnaissance activities.
The technical implementation of this vulnerability demonstrates poor input validation and error handling practices within the MyBB codebase. When error conditions occur during system operation, the framework fails to properly isolate sensitive path information from publicly accessible error logs, creating a persistent information leakage channel. This issue affects both the core MyBB platform and the MyBB Merge System, indicating a fundamental flaw in the error management architecture that requires comprehensive code review and remediation. The vulnerability's persistence across multiple version lines suggests that the underlying architectural flaw has remained unaddressed for an extended period, making it particularly concerning for organizations running legacy installations.
Mitigation strategies for CVE-2015-8977 should focus on immediate version updates to patched releases, specifically upgrading to MyBB 1.6.18 or 1.8.6 and later versions of the MyBB Merge System. Organizations should also implement proper error handling mechanisms that sanitize all error messages before logging, ensuring that no sensitive path information is exposed through error log files. Additional defensive measures include restricting access to error log files through proper file permissions and implementing web application firewalls that can detect and block suspicious error-triggering requests. The vulnerability underscores the importance of secure error handling practices and proper information sanitization, aligning with security best practices outlined in OWASP Top Ten and NIST cybersecurity guidelines for preventing information disclosure vulnerabilities.