CVE-2011-1135 in Serendipity
Summary
by MITRE
Cross-Site Scripting (XSS) in Xinha, as included in the Serendipity package before 1.5.5, allows remote attackers to execute arbitrary code in plugins/ExtendedFileManager/manager.php and plugins/ImageManager/manager.php.
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Analysis
by VulDB Data Team • 11/06/2019
The vulnerability identified as CVE-2011-1135 represents a critical cross-site scripting flaw affecting the Xinha rich text editor component within the Serendipity publishing platform. This vulnerability specifically impacts versions prior to 1.5.5 and exposes the system to remote code execution attacks through maliciously crafted input in the file management plugins. The affected files plugins/ExtendedFileManager/manager.php and plugins/ImageManager/manager.php serve as primary attack vectors where user input is not properly sanitized or validated before being rendered in web responses.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding practices within the Xinha editor's file management interfaces. When users upload or manipulate files through these plugins, the system fails to adequately sanitize user-supplied data before incorporating it into dynamic web content. This creates an environment where attackers can inject malicious javascript code that executes in the context of other users' browsers. The vulnerability operates under CWE-79 which specifically addresses cross-site scripting flaws, where applications fail to properly validate or encode user-controllable data before including it in dynamically generated web pages.
The operational impact of this vulnerability extends beyond simple data theft or session hijacking, as it enables attackers to execute arbitrary code within the victim's browser context. This capability allows malicious actors to perform actions such as stealing cookies, redirecting users to phishing sites, modifying content, or even establishing persistent backdoors through browser-based attack vectors. The attack surface is particularly concerning because these file management plugins are commonly used administrative functions that typically require elevated privileges, making successful exploitation potentially devastating for system integrity and user data protection. The vulnerability aligns with ATT&CK technique T1566 which covers social engineering through malicious file uploads and execution.
Mitigation strategies for CVE-2011-1135 should focus on immediate patching of the Serendipity platform to version 1.5.5 or later where the XSS vulnerabilities have been addressed. Organizations should implement comprehensive input validation measures that sanitize all user-supplied data before processing, particularly in file upload and management interfaces. Additionally, output encoding practices must be strengthened to ensure that any user-controllable data is properly escaped when rendered in web contexts. Security headers such as Content Security Policy should be implemented to add additional layers of protection against XSS attacks. Regular security audits of web applications and their components should be conducted to identify similar vulnerabilities in other third-party libraries and plugins that may be susceptible to similar cross-site scripting attacks.