CVE-2014-9253 in DokuWiki
Summary
by MITRE
The default file type whitelist configuration in conf/mime.conf in the Media Manager in DokuWiki before 2014-09-29b allows remote attackers to execute arbitrary web script or HTML by uploading an SWF file, then accessing it via the media parameter to lib/exe/fetch.php.
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Analysis
by VulDB Data Team • 03/01/2022
The vulnerability identified as CVE-2014-9253 represents a critical security flaw in DokuWiki's Media Manager component that stems from insufficient file type validation mechanisms. This issue affects versions of DokuWiki prior to 2014-09-29b and specifically targets the configuration file conf/mime.conf which controls the whitelist of allowed file types for media uploads. The flaw allows attackers to bypass security restrictions by uploading malicious SWF files, which can then be executed in the context of a victim's browser when accessed through the media parameter of lib/exe/fetch.php. This represents a classic file upload vulnerability that enables arbitrary code execution through web script or HTML injection.
The technical implementation of this vulnerability relies on the default configuration of DokuWiki's mime type handling system, where SWF files are not properly restricted in the whitelist configuration. When users upload SWF files through the Media Manager interface, these files are stored on the server and can be accessed via the fetch.php endpoint with the media parameter. The vulnerability occurs because the system fails to adequately validate file content against the declared mime type, allowing attackers to upload malicious SWF files that contain embedded scripts or HTML code. This flaw is particularly dangerous because SWF files are commonly trusted by web browsers and can execute within the context of the user's session, potentially leading to cross-site scripting attacks or more severe exploitation techniques.
The operational impact of CVE-2014-9253 extends beyond simple script execution, as it creates potential for persistent security breaches within DokuWiki installations. Attackers can leverage this vulnerability to upload malicious content that remains persistent on the server, potentially leading to ongoing security compromise. The vulnerability aligns with CWE-434, which describes insecure file upload handling, and demonstrates how weak input validation can lead to remote code execution. From an attacker's perspective, this vulnerability provides a straightforward path to compromise user sessions and potentially escalate privileges within the DokuWiki environment. The attack vector is particularly concerning because it requires minimal user interaction beyond the initial upload, as the malicious content can be triggered simply by accessing the media parameter through fetch.php.
Organizations using affected versions of DokuWiki should implement immediate mitigations including updating to the patched version 2014-09-29b or later, which includes enhanced file type validation and stricter mime type handling. Security administrators should also consider implementing additional network-level controls such as web application firewalls that can detect and block suspicious file upload patterns. The vulnerability demonstrates the importance of proper input validation and the dangers of relying on default configurations that may not adequately address security requirements. From a defensive standpoint, this vulnerability underscores the need for regular security assessments of file handling mechanisms and proper configuration management practices that align with security standards such as those outlined in the OWASP Top Ten and NIST cybersecurity frameworks. The incident serves as a reminder that even seemingly benign file type restrictions can create significant security risks when not properly implemented and validated.