An issue was discovered in Plex Media Server through 1.24.4.5081-e362dc1ee. An attacker (with a foothold in a endpoint via a low-privileged user account) can access the exposed RPC service of the update service component. This RPC functionality allows the attacker to interact with the RPC functionality and execute code from a path of his choice (local, or remote via SMB) because of a TOCTOU race condition. This code execution is in the context of the Plex update service (which runs as SYSTEM).
The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. This can cause the product to perform invalid actions when the resource is in an unexpected state.
| Link | Tags |
|---|---|
| https://www.plex.tv/media-server-downloads/ | product vendor advisory |
| https://bugsec.com/experts_teams/ | third party advisory |
| https://ir-on.io/2021/12/02/local-privilege-plexcalation/ | third party advisory exploit |
| https://forums.plex.tv/t/security-regarding-cve-2021-42835/761510 | vendor advisory |