The filesystem authentication (condor_io/condor_auth_fs.cpp) in Condor 7.6.x before 7.6.10 and 7.8.x before 7.8.4 uses authentication directories even when they have weak permissions, which allows remote attackers to impersonate users by renaming a user's authentication directory.
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.