University of South Carolina

White Knight: USC researcher hacks for good

By Steven Powell,, 803-777-1923

Wenyuan Xu sits in a Columbia-area apartment with a computer and an antenna. Within a few days she knows which of her neighbors in the complex leave their homes at 8 a.m. and don’t return until 6 p.m. and she knows which neighbors leave their apartments empty for whole weekends at a time.

In the wrong hands, this information could leave residents open to theft and damage. But Xu is on your side. The assistant professor in the University of South Carolina’s College of Engineering and Computing is looking for ways to keep your information secure.

Xu looks for weaknesses in wireless communications systems, often in places where people are rarely thinking about security. She uses her skills to reverse-engineer proprietary hardware and software. She exposes risks then works to push businesses to create devices or methods to more securely transmit information.

Recently, Xu and her students took a look at wireless utility meters. As of 2010, more than a third of all utility meters in the U.S. used wireless automatic meter reading (AMR) technology – 47 million in all. They make it a lot easier for the utility company to gather data on electricity, natural gas and water usage.

But as Xu and her team have shown, it’s possible for their unencrypted broadcasts to be intercepted, giving a sophisticated eavesdropper a window into household activities.

Xu says that much of the focus in the research security community right now is on the next generation of devices, the so-called “smart” meters. Utilities hope that in the future they will be able to use these smart readers to match electricity flow to individual houses with overall demand, enabling much more efficient allocation of resources.

“There’s been a lot of discussion about smart meters and whether they’re secure or not,” Xu said. “But smart meters are not yet widespread. So we wanted to look at the wireless readers common now. Are they secure? Will they leak private information?”

Wireless meters greatly reduce the need for human operators. A single truck can drive through a neighborhood and collect usage information on hundreds of dwellings that previously required a reader to walk to each meter and record data by hand.

Xu reported at a recent conference that they found neither security nor privacy in the representative AMR systems they tested.

Xu’s team was able to reverse-engineer the meter’s transmissions. Once they understood how to read the data, they conducted an eavesdropping experiment in a local apartment complex. Using a modestly priced antenna and laptop located inside the apartment of one of her graduate students, they were able to detect dozens of nearby electricity meters. By adding an inexpensive amplifier to the system, they were able to gather electrical data from every apartment in the complex – hundreds of units up to 500 yards away.

“We were able to detect even further than we expected,” Xu said. “The complex had 408 units, but we were able to see 485, so we were seeing beyond the complex itself.”

The data being transmitted had the potential to be matched to the individual dwellings because the transmitted packets contained an identification number that was stamped on the meter itself.

Beyond raw usage data, a range of information could be deduced from analyzing the meter’s activity, particularly when it came to electricity. “Most electrical meters broadcast data every 30 seconds,” Xu said. “The gas and water meters, because they run on batteries, only transmit data after a wake-up call.”

The detailed electricity data gave information about activities within the household – when the inhabitants got up, went to work and got home, for example. The team was able to deduce that 27 of the apartments within the complex were unoccupied.

That sort of information could be harmful in the wrong hands. Xu is careful not to reveal too much detail in her publications, she said. “We don’t want the bad guys to know too much. It’s about letting the right people know what needs to be better protected.”

The good news is that reliance on what’s often called “security through obscurity” appears to be working. Obtaining personal household data through wireless meters is difficult. What Xu and her team hopes is that drawing attention to the potential for problems might help the industry realize the necessity of designing systems with security in mind.

“The meter data should have been encrypted before transmission and authenticated by readers in the drive-by trucks to prevent the potential misuses that we’ve discovered,” Xu said.

News and Internal Communications

Posted: 11/16/12 @ 12:00 AM | Updated: 11/16/12 @ 3:50 PM | Permalink



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