Groupnotes Inc. Videostream Mac client installs a LaunchDaemon that runs with root privileges. The daemon is vulnerable to a race condition that allows for arbitrary file writes. A low privileged attacker can escalate privileges to root on affected systems.
Every five hours the Videostream LaunchDaemon runs with root privileges to check for updates. During the download, it's possible to replace the update file as any user with a crafted tar archive. The LaunchDaemon process will extract the archive and replace any requested file on the system.
An attacker with low privilege access can overwrite arbitrary files on the affected system. This can be leveraged to escalate privileges to control the root account.
The CERT/CC is currently unaware of a practical solution to this problem.
Thank you to Dan Revah for reporting this issue.
This document was written by Kevin Stephens.