The vast majority of spammers -- 95% - generate more than five SMS messages per hour, and more than 70% send more than 50 per hour. In contrast more than 97% of legitimate messages send fewer than 5 messages per hour, the researchers say.
Spamming trafc volume can be 10 times that of normal traffic, and at certain network junctures can account for 80% to 90% of all SMS traffic, they say.
More than 60% of spammers target phone numbers in the area codes of major cities; the rest spread it around, the researchers say.
Sign up for CIO Asia eNewsletters.