3.1.5.3 reqFlags Processing

[RFC2478], the predecessor to [RFC4178], includes the reqFlags field in the protocol. This field is intended for the client to indicate the requested behavior according to the GSS abstract variables, such as confidentiality and integrity. However, the reqFlags field is not covered by the signature of the message; therefore, it can be tampered with while in transit.

As specified in [RFC4178], use of this field is explicitly discouraged due to the lack of integrity protection, and the acceptor (server) MUST ignore the reqFlags, if present.