code: public void revokeAll(String droppedUser)
      {
          try
          {
              process(String.format("DELETE FROM %s.%s WHERE username = '%s'", Auth.AUTH_KS, PERMISSIONS_CF, escape(droppedUser)));
          }
          catch (RequestExecutionException e)
          {
              logger.warn("CassandraAuthorizer failed to revoke all permissions of {}: {}", droppedUser, e);
          }
      }
docs: Called prior to deleting the user with DROP USER query. Internal hook, so no permission checks are needed here.