The IPTables-Parse module before 1.6 for Perl allows local users to write to arbitrary files owned by the current user.
https://metacpan.org/source/MRASH/IPTables-Parse-1.6/Changes
https://github.com/mtrmac/IPTables-Parse/commit/b400b976d81140f6971132e94eb7657b5b0a2b87