Securing Your Network and Subscribers

Securing Your Network and Subscribers Mobile phone operators and users are all threatened nowadays by malicious usage of SMS systems. There are various methods for sending “free” SMS to any locations around the world by people who are not the actual subscribers of the operator’s network, although they use valid (stolen) SIM information of existing subscribers. Someone has to pay for this traffic, and it will ultimately be the operator, since the subscribers will either complain and ask for refund, or become dissatisfied, which may lead to gossip or churn. SGA-SMSFD, AITIA’s latest SMS Fraud Detection system, allows the operators to filter this nonauthentic traffic and helps avoid its unpleasant consequences.

Alerting, Logging, and Blocking Fraud

SGA-SMSFD can be considered as a firewall protecting the SMS Center (SMSC) in the SS7 world. The operator can assign various treatments to handle suspicious messages - from only logging the event to the extreme case of blocking the SMS and warning the operator staff with an alarm.

Operating Principles

SGA-SMSFD receives several types of SMS-related messages that were sent towards the SMSC. Upon receiving a ForwardSM message, SGA-SMSFD analyzes the signaling message structure, and checks if all fields are filled out according to the expectations; incorrectly given message fields (such as variables related to encoding schemes, network node identification or user identification) yield for suspicion. Then it checks whether the sender of the SMS really resides in the MSC/VLR area that is suggested by the message header - this is done by a HLR interrogation procedure. This analysis has an end-result for each message.