CVE-2015-2969 in PHP Simple Oekaki BBS
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in index.php in LEMON-S PHP Simple Oekaki BBS before 1.21 allows remote attackers to inject arbitrary web script or HTML via the oekakis parameter.
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Analysis
by VulDB Data Team • 07/03/2017
The CVE-2015-2969 vulnerability represents a classic cross-site scripting flaw in the LEMON-S PHP Simple Oekaki BBS software, a web-based bulletin board system designed for image-based posting and discussion forums. This vulnerability specifically affects versions prior to 1.21 and resides within the index.php file, making it a critical security concern for any organization utilizing this software. The flaw manifests when the oekakis parameter is processed without adequate input sanitization or output encoding, creating an avenue for malicious actors to execute arbitrary web scripts or HTML code within the context of other users' browsers.
The technical exploitation of this vulnerability occurs through the improper handling of user-supplied input in the oekakis parameter, which is typically used to pass data related to image posts or user interactions within the oekaki board system. When the application fails to properly validate or escape this input before rendering it in the web page output, attackers can inject malicious scripts that execute in the victim's browser context. This represents a Type 1 XSS vulnerability according to CWE-79, where the application incorporates untrusted data into web pages without proper validation or encoding. The vulnerability is particularly dangerous because it allows attackers to inject scripts that can steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable sophisticated attacks including session hijacking, credential theft, and the deployment of malicious payloads that persist across user sessions. Attackers can craft malicious URLs containing the oekakis parameter with embedded JavaScript that executes when other users view the affected page, potentially compromising the entire user base of the bulletin board system. This vulnerability directly maps to ATT&CK technique T1566.001, which describes the use of malicious content to gain initial access to systems through web-based attacks. The compromised system could serve as a launching point for further attacks within the network, making this vulnerability particularly dangerous in environments where the BBS system is integrated with other applications or serves as a gateway to internal resources.
Mitigation strategies for this vulnerability require immediate patching to version 1.21 or later, which includes proper input validation and output encoding mechanisms. Organizations should implement comprehensive input sanitization techniques that filter or escape special characters before processing user data, particularly in parameters like oekakis that are susceptible to injection attacks. The implementation of Content Security Policy headers can provide additional protection layers by restricting the sources from which scripts can be loaded, effectively mitigating the impact of successful XSS attempts. Regular security assessments of web applications should include thorough testing of input parameters for XSS vulnerabilities, with particular attention to dynamic content generation and user-supplied data handling. This vulnerability underscores the importance of following secure coding practices as outlined in OWASP Top 10 and the need for continuous security monitoring to detect and remediate similar issues in legacy web applications.