Spam isn’t just for your PC anymore. It’s rapidly infecting text messaging, too, which means unsolicited ads for refinancing, discount drugs, and pornography can follow you anywhere you take your mobile phone-and even cost you money, if your carrier charges by the message.

The volume of spam text messages originating from the Internet in North America last year actually exceeded that of legitimate messages, according to Wireless Services of Bellevue, WA. Following the lead of Japan, South Korea, and the European Union, California has passed a law aimed at slowing such messages, and in December the U.S. Congress, as part of the CAN-SPAM Act of 2003, directed the Federal Communications Commission to come up with rules protecting cell-phone users nationwide from unsolicited text messages. But wireless companies and software vendors, worried that mobile spam will deter cell-phone users from subscribing to next-generation data services, aren’t waiting for new regulations before enacting their own measures to stem the tide. Otherwise, the value of these services will be “completely obliterated,” says Jim Manis, president of the Mobile Marketing Association, a trade group focused on the medium.

In November, Wireless Services-one of three companies that handle the text messages sent between the networks of U.S. wireless carriers like Verizon Wireless and SprintPCS-rolled out software that builds on some of the most popular techniques for blocking e-mail spam. “We were getting pressed by our customers to do something,” says Eric Lofdahl, the company’s director of product management.

The technology starts with Bayesian filtering, which spots spam based on its resemblance to messages in a large database of previously identified spam. But it adds a quarantine system. “Maybe there’s a URL that the spammer wants somebody to hit,” Lofdahl explains. “We’ll count how many messages transit our system that have that URL in them over a certain time frame, and if that number exceeds a threshold, we will start diverting those messages into a quarantine area for somebody to look at.” When legitimate messages get quarantined, the company’s spam spotters usually release them within minutes, Lofdahl says.

The company is working to make its spam filters customizable, so that cell-phone owners can decide which messages to accept rather than depend on the carriers’ standards. Right now, says Lofdahl, “If you really are in the market for debt refinancing, you probably aren’t going to get many of the messages you want sent to your cell phone about that.” The company’s improved software, being implemented this year, would let you unblock messages containing certain keywords, such as “debt” or “mortgage.”

Giving wireless subscribers more control over their text message in-boxes is also the goal of software under development at Lucent Technologies’ Bell Labs in Murray Hill, NJ. Lucent’s system looks forward to the near future, when so-called location-aware applications could make mobile spam all the more insidious (see “WhereWare,” TR September 2003). Federal requirements that most cell phones be capable of reporting their geographic location to 911 emergency systems by 2005 have inspired wireless carriers and marketers to dream up non-emergency uses for their newly gained ability to track phones-say, sending you a coffee ad or coupon when you get within a certain range of a caf.

Lucent’s prototype lets carriers create online menus with which customers can specify things like which kinds of businesses they’d like to receive messages from, at what times of the day or week, and within what geographical radius. “If the consumer can block a merchant from viewing his location information, the merchant has no idea they’re passing by,” explains Rick Hull, Bell Labs’ director of network data and services research. Over the coming year, the software will be folded into existing software that handles data moving between the Internet and telecommunications networks.

Meanwhile, even more-exotic spam is starting to show up. In South Korea, Japan, Britain, and parts of the United States, next-generation cellular networks allow high-bandwidth data transfer, so messages can include not just text but also photos and animations.

With multimedia spam already a problem, wireless providers are trying “opt-in” requirements similar to those already in use in Europe to keep such elaborate junk ads under control. In the United Kingdom and other countries, wireless carriers use a system of “common short codes,” five-digit numbers that consumers find on billboards or magazine ads and type into their phones to receive text-based promotions. Last October, U.S. wireless carriers agreed to a similar system.

Of course, clever spammers will keep finding ways to sneak some messages past industry controls. “It’s like those old Mad magazine Spy versus Spy’ cartoons: spammers come up with something, and we have to come up with something to counteract it,” Lofdahl says.

And this means the 150 million cellular subscribers in the United States-the majority of whom own phones capable of two-way text messaging-have little chance of entirely avoiding getting spammed.

Stopping Mobile Spam in its Tracks COMPANY TECHNOLOGY/STATUS Brightmail
San Francisco, CA Software that uses thousands of decoy accounts to detect text message spam and blocks messages from suspect addresses; being tested by European wireless providers Lucent Technologies’ Bell Labs
Murray Hill, NJ System that blocks unsolicited text messages based on location, time, and other factors; will be added to cellular-networking software this year Openwave
Redwood City, CA Software that blocks messages from cellular networks if they arrive in high volume or from untrusted sources; launched in the United States in February 2004 Telcotec
Dublin, Ireland Software for cellular networks that analyzes images in multimedia messages and offers subscribers the option to block adult content; launched in May 2003 Wireless Services
Bellevue, WA Spam-blocking software for cellular networks based largely on established techniques for e-mail spam detection; launched in November 2003