Patent ID: 8326265

Claim:
A method for detecting an unauthorized service message in a communications network, the method comprising the steps of: at a supplementary services network routing node, at least a portion of which is implemented in hardware: receiving a signaling message associated with a supplementary service (SS) message or an unstructured supplementary service data (USSD) message identifying a first network node as a node serving a sender of the SS or USSD message, the signaling message comprising identification information of the sender of the SS or USSD message and first identification information of the first network node; requesting, from a second network node, second identification information identifying a network node serving the sender of the SS or USSD message, wherein requesting the second identification information identifying the network node serving the sender of the SS or USSD message comprises sending a mobile application part (MAP) message to the second network node and receiving from the second network node an address associated with the first network node; comparing the first identification information with the second identification information, wherein comparing the first identification information with the second identification information includes comparing the first N digits of an address associated with the first network node in the first identification information with the first N digits of the address associated with the first network node received from the second network node in order to support systems comprising one or more multi-address mobile switching centers (MSCs); determining whether the SS or USSD message is authorized or not based on the comparison result; and in response to determining that the SS or USSD message is authorized, sending the signaling message associated with the SS or USSD message to the second network node.