CVE-2016-9468 in ownCloud Server
Summary
by MITRE
Nextcloud Server before 9.0.54 and 10.0.1 & ownCloud Server before 9.0.6 and 9.1.2 suffer from content spoofing in the dav app. The exception message displayed on the DAV endpoints contained partially user-controllable input leading to a potential misrepresentation of information.
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Analysis
by VulDB Data Team • 11/22/2022
The vulnerability CVE-2016-9468 represents a content spoofing issue affecting Nextcloud Server versions prior to 9.0.54 and 10.0.1, as well as ownCloud Server versions before 9.0.6 and 9.1.2. This flaw exists within the dav application component that handles web-based distributed authoring and versioning protocols. The vulnerability stems from improper sanitization of user input within exception handling mechanisms, specifically when displaying error messages on DAV endpoints. When certain operations fail or encounter exceptions, the system generates error messages that incorporate user-controllable data directly into the response content without adequate validation or escaping.
The technical implementation of this vulnerability allows attackers to manipulate the content of exception messages by injecting malicious input through DAV requests. This occurs because the DAV application does not properly sanitize or escape user-provided data before incorporating it into error responses. The flaw falls under CWE-79 which specifically addresses cross-site scripting vulnerabilities through improper input handling, and more broadly relates to CWE-116 which covers improper encoding or escaping of output data. Attackers can exploit this by crafting malicious requests that, when processed by the DAV endpoint, result in exception messages containing malicious content such as HTML tags, JavaScript code, or other potentially harmful elements that get rendered in the user's browser context.
The operational impact of this vulnerability extends beyond simple information misrepresentation to potentially enable more sophisticated attacks. While the primary concern is content spoofing that may mislead users about the system state or functionality, the vulnerability creates opportunities for social engineering attacks where users might be tricked into executing malicious actions based on the misleading information presented. The DAV protocol is commonly used for file synchronization and collaboration features, making this vulnerability particularly concerning in environments where users frequently interact with web-based file management systems. An attacker could potentially craft exception messages that appear to come from legitimate system operations, thereby deceiving users into performing unintended actions or revealing sensitive information. This aligns with ATT&CK technique T1566 which covers phishing and social engineering through deceptive content.
Mitigation strategies for CVE-2016-9468 require immediate patching of affected systems to versions that properly sanitize exception messages and user input before rendering them in error responses. Organizations should implement comprehensive input validation and output encoding mechanisms within the DAV application to prevent user-controllable data from being directly incorporated into exception messages. The fix should ensure that all user-provided data is properly escaped or sanitized before being included in any error response, particularly when that data might be rendered in a web browser context. Additionally, security monitoring should be enhanced to detect unusual patterns in DAV endpoint usage that might indicate exploitation attempts, while regular security audits should verify that exception handling code properly implements secure coding practices. System administrators should also consider implementing web application firewalls that can detect and block malicious input patterns targeting this specific vulnerability class.