USSD — Architecture analysis, security threats, issues and enhancements

USSD (Unstructured Supplementary Services Data) is a real-time session oriented technology, used to provide mobile based network and banking services with/without Internet using USSD codes over GSM channel. For banking services using USSD, the Mobile Network Operator (MNO) is used as an interface between the customer and his respective bank. USSD is an user interactive menu driven, cheaper and faster solution and is better than SMS w.r.t to cost, security and channel usage (as SMS uses voice channel always, whereas USSD uses voice channel normally and resorts to a separate channel only when it is busy). It is platform independent, available in multiple regional languages and does not require any software download. USSD is considered as a better choice for non-smartphone users of rural community to avail network services and bank payment solutions. Additional security enhancements in USSD shall make it the best choice and extend its use further. To do security enhancements in USSD, it is necessary to understand its architecture, its benefits, threats and issues. This paper presents the details on USSD architecture, benefits, threats and proposes possible security enhancements in the same to improve the USSD based mobile banking application information security.