CVE-2016-9411 in MyBB
Summary
by MITRE
The Admin control panel in MyBB (aka MyBulletinBoard) before 1.8.7 and MyBB Merge System before 1.8.7 allows remote attackers to obtain the installation path via vectors involving sending mails.
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Analysis
by VulDB Data Team • 08/08/2020
The vulnerability identified as CVE-2016-9411 affects MyBB forums and the MyBB Merge System versions prior to 1.8.7, representing a critical information disclosure flaw that exposes installation paths to remote attackers. This vulnerability resides within the admin control panel functionality and specifically manifests when the system processes mail sending operations, creating an avenue for malicious actors to extract sensitive directory structure information from the affected systems. The flaw fundamentally stems from inadequate input validation and output sanitization within the email handling mechanisms of the administrative interface, allowing attackers to manipulate the system into revealing its physical installation path through crafted requests.
The technical exploitation of this vulnerability occurs through carefully constructed mail sending operations that trigger the disclosure mechanism. When administrators or automated processes attempt to send emails through the vulnerable system, the application fails to properly sanitize the output of internal path references, inadvertently exposing the complete installation directory structure to remote attackers. This type of vulnerability maps directly to CWE-200, which categorizes information exposure flaws that allow unauthorized information disclosure, and specifically aligns with CWE-1244, which addresses improper handling of sensitive information in administrative interfaces. The attack vector leverages the existing mail functionality rather than requiring additional privileges, making it particularly dangerous as it can be exploited by attackers with minimal access rights.
The operational impact of CVE-2016-9411 extends beyond simple information disclosure, as the revealed installation paths provide attackers with crucial reconnaissance data for subsequent exploitation attempts. Knowledge of the exact file system structure enables attackers to craft more targeted attacks including directory traversal exploits, local file inclusion vulnerabilities, and privilege escalation attempts. The exposure of installation paths also facilitates social engineering attacks and can be combined with other vulnerabilities to create more sophisticated attack chains. This vulnerability particularly affects organizations using MyBB forums for community management, business communication, or customer support systems where the disclosure of administrative paths could compromise entire network infrastructures. According to ATT&CK framework categorization, this vulnerability maps to T1083 (File and Directory Discovery) and T1592 (Threat Group TTPs) as it enables attackers to gather critical system information that supports further compromise activities.
Mitigation strategies for CVE-2016-9411 require immediate implementation of version updates to MyBB 1.8.7 or later, as this represents the primary and most effective solution to address the vulnerability. Organizations should also implement network-level restrictions on administrative interfaces, limiting access to trusted IP addresses and implementing proper firewall rules to prevent unauthorized access to the admin control panel. Input validation should be strengthened throughout the email handling components, with proper sanitization of all output parameters that might contain path information. Additionally, organizations should conduct regular security audits of their forum installations, monitor for unauthorized access attempts, and implement proper logging mechanisms to detect exploitation attempts. Security patches should be applied immediately, and the system should be re-evaluated for any potential compromise indicators following remediation efforts.