CVE-2015-2149 in MyBB
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in the administrative backend in MyBB (aka MyBulletinBoard) before 1.8.4 allow remote authenticated users to inject arbitrary web script or HTML via the (1) MIME-type field in an add action in the config-attachment_types module to admin/index.php; (2) title or (3) short description field in an add action in the (a) config-mycode or (b) user-groups module to admin/index.php; (4) title field in an add action in the (c) forum-management or (d) tool-tasks module to admin/index.php; (5) name field in an add_set action in the style-templates module to admin/index.php; (6) title field in an add_template_group action in the style-templates module to admin/index.php; (7) name field in an add action in the config-post_icons module to admin/index.php; (8) "title to assign" field in an add action in the user-titles module to admin/index.php; or (9) username field in the config-banning module to admin/index.php.
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Analysis
by VulDB Data Team • 04/16/2022
The vulnerability CVE-2015-2149 represents a critical cross-site scripting flaw in MyBB's administrative backend that affects versions prior to 1.8.4. This vulnerability resides in the administrative interface of the MyBulletinBoard forum software, where multiple input fields across various administrative modules fail to properly sanitize user input before rendering it in the web interface. The flaw specifically targets authenticated administrative users who possess sufficient privileges to access the backend configuration modules, making it particularly dangerous as it allows attackers with administrative access to execute malicious scripts within the context of other administrators' browsers. The vulnerability is categorized under CWE-79 as a failure to sanitize input, which directly enables XSS attacks that can persistently compromise the administrative environment.
The technical implementation of this vulnerability spans across multiple administrative modules within MyBB's backend, each presenting distinct attack vectors through unsanitized input fields. Attackers can exploit the vulnerability by manipulating the MIME-type field in the config-attachment_types module, or by injecting malicious content into title fields within the config-mycode and user-groups modules, as well as in forum-management and tool-tasks modules. Additionally, the vulnerability extends to style-templates module where name and title fields in add_set and add_template_group actions can be exploited, while the config-post_icons and user-titles modules provide further attack surfaces through their respective name and title fields. The config-banning module also presents a vector through the username field manipulation. These multiple entry points demonstrate a systemic lack of input validation across the administrative interface, creating a comprehensive attack surface that can be leveraged for persistent malicious activities.
The operational impact of CVE-2015-2149 is severe and multifaceted, as it can lead to complete administrative compromise of the MyBB forum system. When exploited, these XSS vulnerabilities can enable attackers to execute arbitrary JavaScript code within the browser context of authenticated administrators, potentially allowing for session hijacking, privilege escalation, or data exfiltration. The attack could result in unauthorized access to sensitive administrative functions, modification of forum content, user management alterations, and even complete system compromise. The persistent nature of XSS attacks means that once exploited, malicious scripts can continue to execute whenever affected administrators access the compromised pages, creating a long-term security threat. This vulnerability directly aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as the injected scripts can execute commands within the administrative context. The impact extends beyond simple data theft, as attackers can manipulate forum configurations, modify user permissions, and potentially establish backdoors for continued access.
Mitigation strategies for CVE-2015-2149 require immediate implementation of patch management protocols to upgrade to MyBB version 1.8.4 or later, which contains the necessary input sanitization fixes. Organizations should implement comprehensive input validation across all administrative interfaces, ensuring that all user-supplied data is properly escaped and sanitized before rendering in web pages. The implementation of Content Security Policy (CSP) headers can provide additional protection against XSS exploitation by restricting script execution. Regular security audits of administrative interfaces should be conducted to identify similar input validation gaps. Network segmentation and privileged access controls can help limit the impact of potential exploitation by restricting administrative access to only necessary personnel and systems. The vulnerability demonstrates the critical importance of maintaining up-to-date software versions and implementing robust input validation mechanisms, as outlined in OWASP Top 10 2021 category A03: Injection. Administrative users should also be trained to recognize potential XSS attack vectors and maintain awareness of suspicious activities within their administrative interfaces.