CVE-2005-3776 in MyBB
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in MyBulletinBoard (MyBB) 1.0 PR2 Rev 686 allow remote attackers to inject arbitrary web script or HTML via (1) the subject field when creating a new thread and (2) information passed to the Reputation system.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 04/30/2019
The vulnerability identified as CVE-2005-3776 represents a critical cross-site scripting flaw affecting MyBulletinBoard version 1.0 PR2 Rev 686. This security weakness resides in the bulletin board's handling of user input within specific functional areas, creating potential entry points for malicious actors to execute unauthorized scripts in the context of other users' browsers. The vulnerability impacts the core functionality of the platform by allowing attackers to manipulate data flow through two distinct pathways that directly interact with user-generated content processing mechanisms.
The technical implementation of this vulnerability stems from inadequate input validation and output sanitization within the MyBB application's thread creation and reputation systems. When users create new threads, the subject field fails to properly sanitize user input, permitting malicious script code to be stored and subsequently executed when other users view the thread. Similarly, the reputation system processes information without sufficient filtering mechanisms, allowing attackers to inject malicious payloads through reputation-related data submissions. This dual attack surface increases the exploitability potential and demonstrates poor defensive programming practices that violate fundamental web application security principles. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws in web applications.
The operational impact of this vulnerability extends beyond simple script injection, potentially enabling attackers to perform session hijacking, deface the bulletin board, steal sensitive user information, or redirect victims to malicious websites. An attacker could craft malicious threads with embedded scripts that execute in the context of legitimate users' browsers, potentially compromising their sessions and accessing private communications. The reputation system vulnerability further amplifies the risk as it could be exploited during normal user interactions, making detection more challenging. This type of vulnerability directly maps to attack techniques described in the ATT&CK framework under T1566 for initial access through malicious content and T1059 for command and control through script injection.
Mitigation strategies for CVE-2005-3776 require immediate implementation of input validation and output encoding mechanisms throughout the affected application components. The most effective approach involves implementing strict sanitization of all user inputs, particularly in fields that directly influence HTML rendering such as thread subjects and reputation data. Web application firewalls should be configured to detect and block suspicious script patterns in HTTP requests. Additionally, developers should implement proper HTML escaping when displaying user-generated content to prevent script execution. Security patches should be applied immediately to upgrade to a patched version of MyBB, as this vulnerability represents a known flaw that has been addressed in subsequent releases. Organizations should also implement regular security assessments and input validation testing to prevent similar vulnerabilities from emerging in other application components. The remediation process should include comprehensive code reviews focusing on user input handling and output encoding practices to ensure adherence to secure coding standards and prevent recurrence of similar issues.