CVE-2024-4030

On Windows a directory returned by tempfile.mkdtemp() would not always have permissions set to restrict reading and writing to the temporary directory by other users, instead usually inheriting the correct permissions from the default location. Alternate configurations or users without a profile directory may not have the intended permissions.

If you’re not using Windows or haven’t changed the temporary directory location then you aren’t affected by this vulnerability. On other platforms the returned directory is consistently readable and writable only by the current user.

This issue was caused by Python not supporting Unix permissions on Windows. The fix adds support for Unix “700” for the mkdir function on Windows which is used by mkdtemp() to ensure the newly created directory has the proper permissions.

Weakness

During installation, installed file permissions are set to allow anyone to modify those files.

Potential Mitigations

• Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
• Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/1.html
• https://cwe.mitre.org/data/definitions/127.html
• https://cwe.mitre.org/data/definitions/81.html

References

• https://github.com/python/cpython/commit/35c799d79177b962ddace2fa068101465570a29a
• https://github.com/python/cpython/commit/5130731c9e779b97d00a24f54cdce73ce9975dfd
• https://github.com/python/cpython/commit/66f8bb76a15e64a1bb7688b177ed29e26230fdee
• https://github.com/python/cpython/commit/6d0850c4c8188035643586ab4d8ec2468abd699e
• https://github.com/python/cpython/commit/81939dad77001556c527485d31a2d0f4a759033e
• https://github.com/python/cpython/commit/8ed546679524140d8282175411fd141fe7df070d
• https://github.com/python/cpython/commit/91e3669e01245185569d09e9e6e11641282971ee
• https://github.com/python/cpython/commit/94591dca510c796c7d40e9b4167ea56f2fdf28ca
• https://github.com/python/cpython/commit/c8f868dc52f98011d0f9b459b6487920bfb0ac4d
• https://github.com/python/cpython/commit/d86b49411753bf2c83291e3a14ae43fefded2f84
• https://github.com/python/cpython/commit/e1dfa978b1ad210d551385ad8073ec6154f53763
• https://github.com/python/cpython/commit/eb29e2f5905da93333d1ce78bc98b151e763ff46
• https://github.com/python/cpython/issues/118486
• https://mail.python.org/archives/list/security-announce@python.org/thread/PRGS5OR3N3PNPT4BMV2VAGN5GMUI5636/
• https://security.netapp.com/advisory/ntap-20240705-0005/