5.1 Security Considerations for Implementers

SSTP uses cryptographic algorithms for optional initial authentication of devices and users. SSTP provides no protection against connection take-over, eavesdropping, or message modification, insertion, or deletion. Nor does it provide built-in message encryption. These security features can be handled by higher-layers. For the purposes of specifying the SSTP protocol and message formats, the authentication and security registration payloads are assumed to be opaque binary fields.

SSTP supports application-level authentication of device users via the AuthenticationToken field in the Connect and ConnectResponse commands. The SSTP Security protocol Attach/Register command [MS-GRVSSTPS], hosted by an intermediary relay server, can then process the defined token to provide basic authentication of users connecting to a relay server.