CVE-2012-5903 in SMF
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Simple Machines Forum (SMF) 2.0.2 allows remote attackers to inject arbitrary web script or HTML via the scheduled parameter to index.php.
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Analysis
by VulDB Data Team • 04/18/2025
The Cross-site scripting vulnerability identified as CVE-2012-5903 affects Simple Machines Forum version 2.0.2, representing a critical security flaw that enables remote attackers to execute malicious scripts within the context of affected user sessions. This vulnerability resides in the forum's handling of user input through the scheduled parameter in the index.php script, creating an avenue for attackers to inject arbitrary web script or HTML code into the application's response. The flaw demonstrates characteristics consistent with CWE-79, which specifically addresses Cross-site Scripting vulnerabilities where untrusted data is improperly integrated into web pages without adequate sanitization or encoding measures.
The technical implementation of this vulnerability occurs when the SMF application fails to properly validate or sanitize the scheduled parameter received through HTTP requests. When users navigate to the index.php page with a maliciously crafted scheduled parameter, the application processes this input without sufficient input validation, allowing attacker-controlled content to be rendered in the browser context of legitimate users. This creates a persistent XSS vector that can be exploited across multiple user sessions, potentially enabling attackers to steal session cookies, perform unauthorized actions on behalf of users, or redirect victims to malicious websites. The vulnerability's exploitation requires minimal privileges and can be executed through standard web browser interactions, making it particularly dangerous in environments where forum administrators and users have varying levels of trust.
The operational impact of this vulnerability extends beyond simple script injection, as it provides attackers with potential access to sensitive user data and session information. Successful exploitation could result in account takeover scenarios where attackers gain unauthorized access to user accounts, potentially leading to data breaches, content manipulation, or the propagation of malicious payloads throughout the forum community. The vulnerability affects the integrity and confidentiality of user communications within the forum environment, undermining the trust users place in the platform's security mechanisms. Organizations relying on SMF 2.0.2 for community engagement or collaborative work environments face significant risk exposure, particularly in scenarios where sensitive information is shared through forum discussions.
Mitigation strategies for this vulnerability should prioritize immediate patching of the affected SMF version to the latest available release, which includes proper input validation and sanitization measures for the scheduled parameter. Security administrators should implement comprehensive input validation routines that filter or encode all user-supplied data before processing, particularly focusing on parameters that are directly rendered in web responses. The implementation of Content Security Policy headers can provide additional defense-in-depth measures by restricting the sources from which scripts can be executed within the forum environment. Regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other components of the application stack, while user education regarding the risks of clicking suspicious links or visiting untrusted websites remains essential. This vulnerability aligns with ATT&CK technique T1566, which encompasses social engineering tactics that leverage web-based attack vectors to compromise user systems and access sensitive information.