CVE-2014-9304 in Plex Media Server
Summary
by MITRE
Plex Media Server before 0.9.9.3 allows remote attackers to bypass the web server whitelist, conduct SSRF attacks, and execute arbitrary administrative actions via multiple crafted X-Plex-Url headers to system/proxy, which are inconsistently processed by the request handler in the backend web server.
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Analysis
by VulDB Data Team • 12/31/2024
The vulnerability identified as CVE-2014-9304 affects Plex Media Server versions prior to 0993, presenting a critical security flaw that enables remote attackers to circumvent access controls and execute unauthorized administrative operations. This vulnerability specifically targets the web server's whitelist mechanism and exposes a significant weakness in the request handling process within the backend web server architecture. The flaw manifests through the inconsistent processing of X-Plex-Url headers when making requests to the system/proxy endpoint, creating a pathway for malicious actors to exploit the system's security controls.
The technical implementation of this vulnerability stems from improper validation and inconsistent handling of the X-Plex-Url header parameter within the Plex Media Server's request processing pipeline. When attackers craft malicious X-Plex-Url headers and submit them to the system/proxy endpoint, the backend web server fails to consistently enforce the whitelist restrictions that should prevent unauthorized access to administrative functions. This inconsistency in request handling creates a condition where the server processes these headers in a manner that bypasses normal security controls, allowing attackers to manipulate the server's behavior through crafted HTTP requests.
The operational impact of this vulnerability extends beyond simple access control bypass, as it enables sophisticated server-side request forgery attacks that can lead to complete administrative compromise. Attackers can leverage this vulnerability to execute arbitrary administrative actions on the affected server, potentially gaining full control over the media server's configuration, user management, and content access controls. The ability to conduct SSRF attacks through this vector means that attackers can manipulate the server to make requests to internal systems, potentially expanding their attack surface and enabling further reconnaissance or exploitation of internal network resources.
Security implications of CVE-2014-9304 align with CWE-829, which addresses the inclusion of untrusted input in security decisions, and demonstrate characteristics consistent with ATT&CK technique T1071.004 for application layer protocol manipulation. The vulnerability represents a critical weakness in the server's input validation and access control mechanisms, where the inconsistent processing of headers creates an exploitable gap in the security architecture. Organizations running affected versions of Plex Media Server face significant risk of unauthorized access and potential data compromise, as the vulnerability can be exploited remotely without requiring authentication credentials.
Mitigation strategies for this vulnerability should prioritize immediate patching to version 0.9.9.3 or later, which contains the necessary fixes to address the inconsistent header processing behavior. Network administrators should implement additional monitoring for unusual X-Plex-Url header patterns and consider implementing network-level controls to restrict access to the system/proxy endpoint. The remediation approach should also include reviewing and strengthening the server's input validation mechanisms to ensure consistent enforcement of whitelist restrictions across all request handling pathways, particularly focusing on header parameter validation and access control decision points.