PYSEC-2023-292

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PYSEC-2023-292

Summary:

Details: 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.

References: https://github.com/pyinstaller/pyinstaller/security/advisories/GHSA-9w2p-rh8c-v9g5, https://github.com/pyinstaller/pyinstaller/pull/7827, https://github.com/python/cpython/blob/0fb18b02c8ad56299d6a2910be0bab8ad601ef24/Lib/shutil.py#L623, https://lists.fedoraproject.org/archives/list/[email protected]/message/ISRWT34FAF23PUOLVZ7RVWBZMWPDR5U7/, https://lists.fedoraproject.org/archives/list/[email protected]/message/2K2XIQLEMZIKUQUOWNDYWTEWYQTKMAN7/