CVE-2016-6847 in OX AppSuite
Summary
by MITRE
An issue was discovered in Open-Xchange OX App Suite before 7.8.2-rev8. SVG files can be used as mp3 album covers. In case their XML structure contains script code, that code may get executed when calling the related cover URL. Malicious script code can be executed within a user's context. This can lead to session hijacking or triggering unwanted actions via the web interface (sending mail, deleting data etc.).
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Analysis
by VulDB Data Team • 07/08/2019
The vulnerability CVE-2016-6847 represents a critical security flaw in Open-Xchange OX App Suite versions prior to 7.8.2-rev8, where the application fails to properly sanitize SVG file content when used as album cover images for mp3 files. This issue stems from the application's improper handling of XML structures within SVG files, creating a vector for cross-site scripting attacks. The flaw specifically arises when the application processes SVG files that contain embedded script code within their XML structure, allowing malicious payloads to execute in the context of authenticated users.
The technical implementation of this vulnerability involves the application's failure to implement proper input validation and sanitization for SVG file uploads. When users upload mp3 files with SVG album covers, the system does not properly parse or sanitize the XML content within these files, particularly the script elements that may be embedded within the SVG structure. This processing error creates a path where malicious script code can be executed when the cover image URL is accessed, as the application treats the SVG file as a static image while inadvertently executing embedded JavaScript code. The vulnerability is categorized under CWE-79 Improper Neutralization of Input During Web Page Generation, which specifically addresses the failure to properly escape or sanitize user-controllable data before including it in web page content.
The operational impact of this vulnerability is significant, as it enables attackers to execute malicious code within the context of authenticated user sessions. This creates a pathway for session hijacking attacks where attackers can steal user credentials and maintain persistent access to the application. Additionally, the vulnerability allows for the triggering of unwanted actions through the web interface, including sending unauthorized emails, deleting data, or performing other malicious operations that the compromised user has permissions to execute. The attack requires minimal user interaction beyond the normal process of accessing the maliciously crafted mp3 file with the embedded SVG cover, making it particularly dangerous in environments where users frequently interact with multimedia content.
Mitigation strategies for this vulnerability include immediate upgrading to Open-Xchange OX App Suite version 7.8.2-rev8 or later, which contains the necessary patches to properly sanitize SVG file content. Organizations should implement additional security controls such as strict file type validation and content filtering for all uploaded SVG files, ensuring that script elements are removed or properly escaped during the upload process. Network-based solutions should include web application firewalls that can detect and block malicious SVG content, while also implementing proper access controls and monitoring for suspicious activities related to file uploads. The vulnerability aligns with ATT&CK technique T1059.007 Command and Scripting Interpreter: JavaScript, highlighting the importance of proper input sanitization and output encoding to prevent script execution in web applications. Security teams should also consider implementing regular security assessments and penetration testing to identify similar vulnerabilities in other components of their web applications.