In an attempt to beef up security measures in the past, TSA airport scanners controversially stripped away any doubts that you were concealing a dangerous weapon. But a new study found that while these scanners could see through traveler's clothes, it couldn't spot bombs or guns.
The study, presented Thursday at the Usenix security conference in San Diego, found that simply covering contraband with plastic or under clothing obscures the item from the monitors of the Rapiscan Secure 1000 Single Pose full-body scanner.
The Transportation Safety Administration (TSA) popularly used the Rapiscan Secure 1000 over a period of four years before it was discontinued. TSA stopped using the scanner not because it could be breached, but because of public complaints that agents would be able to see naked images of passengers.
Even though the scanners are not in use in U.S. airports anymore, the scanners are still used in airports in Rwanda, Tanzania and Kenya. Since discontinuing them in U.S. airports, TSA sold the Rapiscan Secure 1000s at a discounted price to be used in government security checkpoints, courthouses and prisons. The scanners are currently used in jails in Grand Traverse Country, Mich., and Wilkes, N.C.
"What does this say about how these scanners were tested and acquired in the first place?" asks J. Alex Halderman, one of the study's co-authors. "It says there's something wrong with the government's process."
The problem, Halderman says, is that the process "is secret and not independent."
Computer security experts at the University of California at San Diego purchased a Rapiscan Secure 1000 on eBay for $49,5000 for the study. They purchased it in 2012 when the scanners were still used in U.S. airports.
The researchers tried smuggling weapons past the scanner, by taping a gun to the side of a person's body or sewing it into a pant leg. Only fully metal guns could be completely concealed against the scanner's black background. Tapping a knife to a person's back with thick layer of tape hid the weapon from the scanner as well.
They found that bombs could be as easily concealed as the other weapons. They successfully concealed a 200-gram pancake of putty that mirrored the same properties of explosives by molding it onto the person's torso. A detonator of different material could be hid in the belly button.
"They might stop a naive attacker. But someone who applied just a bit of cleverness to the problem would be able to bypass them. And if they had access to a machine to test their attacks, they could render their ability to detect contraband virtually useless," says Halderman.
The study found that the Rapiscan Secure 1000 software was not so secure either. The software could be hacked to cover up sections of the body that would make contraband undetectable.
These are just some examples of the ways the bombs and other weapons could be hidden. "We're not trying to provide recipes to attack actual devices in the field," says UCSD researcher Keaton Mowery.
The researchers presented their finding to both the TSA and Rapiscan earlier this year, but did not receive any feedback.
U.S. airports now use the ProVision L3, which was reconfigured to prevent an invasion of privacy for travelers.