More Spammers Take Advantage of Location Data
During 2013, a growing number of spammers took advantage of location information encoded in phone numbers to send geo-specific spam, reports Cloudmark, a company that provides messaging security software.
While many regions around the world assign mobile phone numbers to arbitrary pre-assigned blocks reserved specifically for mobile devices, many North American and Caribbean countries have taken a different approach, the company notes in its "2013 Global Messaging Threat Report." The North American Numbering Plan assigns numbers—mobile and landline—to the local exchange dedicated to the geographic region in which they are first registered. In these NANP countries, area codes provide a convenient way to correlate phone numbers with a specific geographic region.
For example, Cloudmark says, New York City's Manhattan borough is assigned area codes 212 and 646. While the portability of mobile numbers allows for users to relocate elsewhere and thereby introduce an error, these area codes are largely representative of the population to which they are assigned.
"Advertisers, spammers and attackers in the United States have long since known of this phenomenon and use it to great effect for targeted messaging," the report states.
Residents of southern Florida are quite familiar with such targeted advertising. The area is home to three of the most popular area codes for SMS spam in the country. During 2013, mobile subscribers in the 954, 305 and 786 area codes reported the first, fourth and sixth highest volumes respectively of SMS spam for any single area code in the U.S.
In fact, one of every 10 SMS spam messages landing on U.S. phones ends up in south Florida, and more than half of those messages come from a single local company in the business of buying junk cars, Cloudmark says. Limited by the cost of hauling these junk cars long distances, the spammers choose to focus their SMS advertisements on nearby numbers.
While these area-code-specific techniques are not widely used yet, Cloudmark says they could be problematic if they become widespread. Also, local attacks might be too low impact to attract the attention of law enforcement.
"However, overall SMS spam levels could see a dramatic rise if unscrupulous businesses all over North America turn to this form of unsolicited, targeted advertising in their local markets," the report warns.
Historically, gift card scams had dwarfed other forms of SMS spam, Cloudmark says. But due to an abrupt end to gift card scams in 2013, bank and account phishing attacks were at the top of the list of most prolific SMS spam types: They accounted for 20 percent of the nation's reported SMS spam.
During 2013, 67 percent of SMS spam messages lured U.S.-based victims with various financial offers, according to the report.