D.3 SMS Message Manipulation or Spoofing
Phishing or ad messages can be sent on behalf of arbitrary subscribers or
services using the MT-ForwardSM and the
MO-ForwardSM methods.
MT-ForwardSM is designed for delivering incoming
messages and can be used by attackers to generate forged incoming SMS
messages. Unauthorized usage of MO-ForwardSM allows sending
messages from subscribers at their expense.