PyInstaller bundles a Python application and all its dependencies into a single package. A PyInstaller built application, elevated as a privileged process, may be tricked by an unprivileged attacker into deleting files the unprivileged user does not otherwise have access to. A user is affected if all the following are satisfied: 1. The user runs an application containing either matplotlib
or win32com
. 2. The application is ran as administrator (or at least a user with higher privileges than the attacker). 3. The user's temporary directory is not locked to that specific user (most likely due to TMP
/TEMP
environment variables pointing to an unprotected, arbitrary, non default location). Either: A. The attacker is able to very carefully time the replacement of a temporary file with a symlink. This switch must occur exactly between shutil.rmtree()
's builtin symlink check and the deletion itself B: The application was built with Python 3.7.x or earlier which has no protection against Directory Junctions links. The vulnerability has been addressed in PR #7827 which corresponds to pyinstaller >= 5.13.1
. Users are advised to upgrade. There are no known workarounds for this vulnerability.