PT-2021-23689 · Plex · Plex Media Server

Published 2021-12-08 · Updated 2021-12-13 · CVE-2021-42835

Positive Technologies (AI Summary)

CVSS v3.1

7.0

High

Base vector

AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions Plex Media Server versions through 1.24.4.5081-e362dc1ee

Description An issue allows an attacker with a foothold in an endpoint via a low-privileged user account to access the exposed RPC service of the update service component. The RPC functionality enables the attacker to interact with it and execute code from a path of their choice, either locally or remotely via SMB, due to a TOCTOU race condition. This code execution occurs in the context of the Plex update service, which runs as SYSTEM.

Recommendations For versions through 1.24.4.5081-e362dc1ee, consider restricting access to the RPC service of the update service component to minimize the risk of exploitation. As a temporary workaround, avoid using the RPC functionality until a patch is available. At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

Time Of Check To Time Of Use

Weakness Enumeration

CWE-367

Related Identifiers

CVE-2021-42835

Affected Products

Plex Media Server

References · 7

• 🔥 https://github.com/netanelc305/PlEXcalaison · Exploit
• 🔥 https://ir-on.io/2021/12/02/local-privilege-plexcalation · Exploit
• https://plex.tv/media-server-downloads · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-42835 · Security Note
• https://forums.plex.tv/t/security-regarding-cve-2021-42835/761510 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2021-42835 · Vendor Advisory
• https://bugsec.com/experts_teams · Note