Introduction
In past recent years, fraud in the telecommunication industry becomes one of major problem for a
telecommunication operator, which is growing dramatically. It has undoubtedly become a
significant source of revenue losses and bad debts to the telecommunication industry, and with the
expected continuing growth in revenue, it can be expected that fraud will increase proportionally.
It has become a fundamental reason for revenue losses in the industry of telecommunications. This
study focuses on International call fraud detection based on past call records. It proposes a new
fraud detecting technique in IDD calls by analyzing the CDRs of roaming subscribers. SIM Boxes
(also known as GSM Gateways) causes international interconnect revenue losses for mobile
operators by bypassing legal connecting routes, which makes the connection operators lose
millions of wholesale minutes.
Bypass fraud is the unauthorized insertion of traffic onto another carrier's network. This scenario
also called as interconnect fraud, GSM gateway fraud, or SIM boxing. This type of scenario
requires that the fraudsters access advanced technology, capable of making international calls
appear to be cheaper, domestic calls, effectively "bypassing" the typical payment system for
international calling. This scenario happens when fraudsters accumulate an incoming international
call through the Internet via Voice over Internet Protocol (VoIP) and then inject it back to the
destination country's telecom network as a local call using local SIM (Subscriber Identity Module)
cards installed in a device called SIMbox. Therefore, the call reached the called party with a local
CLI (Calling Line Identity) and was billed as a local call. Therefore, detection and termination of
such fraudulent phone numbers with minimum delay allow us to regain a significant portion of
revenue and effectively control this kind of fraud.
We can divide Bypass fraud into two major categories as On-net bypass and Off-net Bypass. Onnet bypass means fraudsters use the SIM cards of the same network of the destination number. An
on-net is the typical case in most countries as calls within the exact network cost much lower than
charges for other operators or international calls. In Off-net bypass, fraudsters use a different
operator's SIM card in the same country as the destination number. An off-net happens when local
interconnection charges are much lower than international interconnection charges. In some
countries, local interconnection charges are much closer to the international interconnection
charges.
Anomaly detection has been conducted in real-time. An ABC Telecommunication company is
already using Paid Software for this process. I hope to consider the previous data set in this
research to verify the above-mentioned paid software's output (fraudulent numbers).