Plex Media Server is a widely used digital media server and management software developed by Plex, Inc. It allows users to organize, manage, and stream digital video, music, and photo collections from a centralized library. Plex Media Server is used by individuals, families, and businesses for media consumption and entertainment purposes. It supports a wide range of devices, enabling seamless media streaming across smart TVs, streaming devices, smartphones, and computers. Users can easily access their media libraries over local networks or remotely on supported devices. Due to its popularity, Plex Media Server is a prime target for identifying and mitigating potential security vulnerabilities.
The vulnerability detected in Plex Media Server is a Server-Side-Request-Forgery (SSRF), which occurs when an attacker can manipulate server-side scripts to initiate requests to unauthorized destinations. This specific SSRF vulnerability arises due to improper validation of the 'protocol' parameter in the /player/timeline endpoint. Attackers exploiting this vulnerability can force the server to send POST requests to arbitrary destinations. Such malicious actions do not require authentication, expanding the attack vector, especially from external threat actors. The vulnerability is particularly harmful as it could potentially be used for internal network reconnaissance or data exfiltration.
The SSRF vulnerability in Plex Media Server is linked to improper handling of the X-Plex-Token value combined with the 'protocol' parameter. The vulnerability is found in systems running versions earlier than 1.43.3.10861 and relies on the /player/timeline endpoint. An attacker can provide manipulated data with any X-Plex-Token value, circumventing standard authorization checks. This allows them to craft requests that appear to be from the server itself, potentially accessing restricted internal resources or leaking sensitive information. Additionally, the vulnerability exploits the player protocol capabilities to manipulate server behavior.
When exploited by malicious individuals, this vulnerability can lead to significant security issues within an organization. Potential effects include unauthorized access to protected internal services, unexpected network traffic leading to bandwidth consumption or overload, and exposure to internal data leakage. Attackers could gain insight into private network structures, launch further internal attacks, or exfiltrate sensitive information using the affected server as a proxy. These actions could compromise the integrity and confidentiality of personal or organizational data.
REFERENCES
- Immediately update Plex Media Server to version 1.43.3.10861 or later.
- Regularly monitor and apply security patches released by Plex, Inc.
- Audit server logs for any unusual activities or unauthorized requests.
- Restrict server network permissions to limit external access to essential services only.
- Implement application-level security controls like web application firewalls to detect and block SSRF attempts.
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