Hackers could clog and cripple mobile phone service in U.S. cities by inundating networks with text messages, a study found.
New methods of sending text messages to cellphones using the Web and e-mail, while facilitating communication, also have made it easier to overload mobile networks, the study said.
Hackers, who infiltrate computer networks, could flood Manhattan's mobile phone system by sending 165 messages a second. Although cellular-phone service has failed in disasters such as the Sept. 11 attacks, text messaging has largely been reliable and an important part of communicating, the study said.
"Sophisticated users using a complicated apparatus might be able to exploit this," Patrick D. McDaniel, one of the Pennsylvania State University computer scientists who led the study, said Wednesday.
Text messages and mobile calls travel over the same channels, so separating them on different channels would help, the study said. Carriers also could limit the rate at which messages are transmitted and limit the number of recipients for any one message sent from the Web.
The study "states what we in the industry have known for years," said Nancy Stark, a spokeswoman for Verizon Wireless, the second-largest U.S. mobile phone service provider. "We deal with this issue all the time with spam and thwarting that threat on the network." Spam is a term for unwanted e-mail, typically sent by commercial interests.
Sprint Nextel Corp., the third-largest U.S. wireless and local-telephone company, has safeguards that flag unusual activity, a spokesman said..
Hackers would have to use multiple computers to attempt such an attack, the scientists said. A large-scale assault could come if hackers take over a moderate-size collection of computers, according to the study.