Ecosyste.ms: Advisories

Security Advisories: GSA_kwCzR0hTQS05dzJwLXJoOGMtdjlnNc4AA3pj

Local Privilege Escalation in Windows

Impact

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:

• The user runs an application containing either matplotlib or win32com.
• The application is ran as administrator (or at least a user with higher privileges than the attacker).
• 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:
  • 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
  • The application was built with Python 3.7.x or earlier which has no protection against Directory Junctions links

Patches

The vulnerability has been addressed in https://github.com/pyinstaller/pyinstaller/pull/7827 which corresponds to pyinstaller >= 5.13.1

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?

No workaround, although the attack complexity becomes much higher if the application is built with Python >= 3.8.0.

Permalink: https://github.com/advisories/GHSA-9w2p-rh8c-v9g5
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS05dzJwLXJoOGMtdjlnNc4AA3pj
Source: GitHub Advisory Database
Origin: Unspecified
Severity: High
Classification: General
Published: 5 months ago
Updated: 5 months ago

CVSS Score: 8.8
CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Identifiers: GHSA-9w2p-rh8c-v9g5, CVE-2023-49797
References:

• https://github.com/pyinstaller/pyinstaller/security/advisories/GHSA-9w2p-rh8c-v9g5
• https://nvd.nist.gov/vuln/detail/CVE-2023-49797
• 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/
• https://github.com/advisories/GHSA-9w2p-rh8c-v9g5

Repository: https://github.com/pyinstaller/pyinstaller
Blast Radius: 34.2

Affected Packages