Operating systems have global directories where any user has write access. Those folders are mostly used as temporary storage areas like ``/tmp`` in Linux based systems. An application manipulating files from these folders is exposed to race conditions on filenames: a malicious user can try to create a file with a predictable name before the application does. A successful attack can result in other files being accessed, modified, corrupted or deleted. This risk is even higher if the application runs with elevated permissions.
This rule raises an issue whenever it detects a hard-coded path to a publicly writable directory like ``/tmp`` (see examples bellow). It also detects access to environment variables that point to publicly writable directories, e.g., ``TMP`` and ``TMPDIR``.
