A "one ring and cut" scam that places brief missed calls from premium or high-cost numbers so recipients call back and generate revenue for the fraudster.
Wangiri is a Japanese term meaning roughly "one ring and drop". The fraudster places huge numbers of very short calls, often hanging up after a single ring, from international numbers that pay out termination revenue. Some recipients see the missed call and return it, and every minute they spend on the line earns the fraudster money.
Variants try to keep callers on the line longer, for example by playing a recording that sounds like a person in distress or a hold message. A related pattern sends voicemails or texts urging a callback to the same kind of number. Because each individual call is brief and cheap, the inbound phase can run at very large scale with little cost to the fraudster.
From the network side, the inbound leg looks like a burst of extremely short calls from a narrow set of foreign numbers to many subscribers. The outbound leg looks like an unusual number of customers suddenly calling the same international destination. Correlating both legs, inbound missed calls followed by outbound callbacks to the same ranges, gives a much clearer picture than watching either one alone.
Why it matters to carriers
Terminating providers can spot and suppress the inbound flood, and originating providers can warn or block callbacks to known Wangiri destinations. Because the losses land on your subscribers' bills, unchecked Wangiri also turns into disputes, credits, and churn, so it is worth monitoring both legs of the pattern.