An unprivileged (non-admin) user can exploit an Improper Access Control vulnerability in the Cloudflare WARP Client for Windows (<= 2022.12.582.0) to perform privileged operations with SYSTEM context by working with a combination of opportunistic locks (oplock) and symbolic links (which can both be created by an unprivileged user). After installing the Cloudflare WARP Client (admin privileges required), an MSI-Installer is placed under C:\Windows\Installer. The vulnerability lies in the repair function of this MSI. ImpactAn unprivileged (non-admin) user can exploit this vulnerability to perform privileged operations with SYSTEM context, including deleting arbitrary files and reading arbitrary file content. This can lead to a variety of attacks, including the manipulation of system files and privilege escalation. PatchesA new installer with a fix that addresses this vulnerability was released in version 2023.3.381.0. While the WARP Client itself is not vulnerable (only the installer…