iPad, iPhone device numbers can give up users' identities

Researcher shows how they can link to Facebook profiles

The device number attached to an iPhone, iPad or iPod Touch can be used to reveal a user’s identity, according to a report in Wired.

A security researcher recently reported a flaw in the unique device identifier stored on each of the devices that allows some applications to be linked to the user’s Facebook profile.

A UDID is permanently connected to a device but is not supposed to be attached to personal information. However, the researcher, Aldo Cortesi, found that a gaming network used in some apps to link players was sometimes transmitting UDID numbers attached to personal information.

“Few Apple users realize just how widely their UDIDs are used,” Cortesi writes in describing his discovery. “Research shows that 68 percent of apps silently send UDIDs to servers on the Internet. This is often accompanied by information on how, when and where the device is used.”

In December 2010, the Wall Street Journal reported that it had tested 101 smart-phone apps and that 56 of them sent UDID information to tracking companies.

UDIDs are different from the Integrated Circuit Card ID numbers on devices’ SIM cards, which were involved in a high-profile hack last June, when those numbers and the e-mail addresses for about 120,000 iPad 3G users were exposed on AT&T’s website. 

At first, it seemed that there was no real threat to those iPad users, which included some well-known people and some members of the federal government. But security experts said the numbers, which are printed on a device’s SIM card and sometimes on the product box, could be used to gain information about the owners, although the process would be difficult.

Two hackers working for an organization called Goatse Security were indicted in connection with the incident in January.


About the Author

Kevin McCaney is a former editor of Defense Systems and GCN.


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