'Relay attack' car thefts are increasing in Japan. Footage includes an actual crime scene captured by a security camera provided by the owner of the targeted car. (Ken Hasegawa)

A man watched in disbelief as video footage showed two thieves needing only five seconds to break into his supposedly highly secure Lexus LS500 parked at his home in Higashi-Osaka, Osaka Prefecture.

“That was too easy,” the 35-year-old luxury car owner said.

The vulnerability of smart key systems, the latest in anti-theft devices in the global auto market, is increasingly being exposed in Japan, baffling vehicle owners and police alike.

Like their counterparts in Europe and the United States, auto thieves in Japan are using the latest technologies to deploy a technique known as a “relay attack,” according to police.

In a smart key system, the car and a key fob send weak signals to each other to communicate and check ID. The individual with the key fob can open the car’s door and start the engine by simply pushing a button. Normally, the key fob and the car must be in close proximity of around a meter to communicate.

Relay attacks are usually committed by two individuals working as a pair, according to the Japan Security Systems Association in Tokyo and other organizations.

One person stands close to the key fob, for example, just outside a home or next to the car owner, and uses a special device that collects the fob’s signal. The device relays the signal to another device carried by the accomplice who is located near the targeted vehicle.

The vehicle falsely detects a nearby key fob and unlocks itself and starts the engine. The two thieves then get into the vehicle and drive away.

After that, they alter ID information to allow the vehicle to be operated with another key, and then sell the stolen vehicle on the black market or to a chop shop, security officials said.

Cases of relay attacks have been reported for years around Europe and in the United States, according to automobile industry sources. Industry groups in Germany and British police have alerted vehicle owners about the break-in technique by publicly releasing video footage of burglary scenes.

According to the National Police Agency’s white papers, more than 60,000 auto thefts were confirmed in Japan in 2002. The number plummeted to 10,213 in 2017, when smart keys became popular anti-theft systems.

In the Higashi-Osaka case in September last year, a security camera set up in a house captured the relay attack from start to finish.

A masked man approached the parking space at the private residence, carrying a device connected to a cord extended from a backpack. As he turned the device toward the house, the hazard lights of the parked Lexus blinked, indicating its doors had been unlocked. The apparent accomplice appeared near the vehicle.

The smart key was about 10 meters from the Lexus when the masked man started the process.

However, the thieves ran away empty-handed. The Lexus owner found signs that the engine start button had been pushed twice. The engine did not start for some reason, and the thieves presumably gave up.

The Lexus owner is considering to ask automobile makers to take additional crime-prevention measures.

According to the Osaka prefectural police, an apparent relay attack theft occurred in Ibaraki in January this year. Another incident was reported in Moriguchi in May 2018.

Investigators said they had never heard of a relay attack case before that.

Mitsuhiro Kunisawa, an automobile critic who has blogged about the risks of relay attacks, said it had been difficult to read IDs in the smart key system.

“It was believed to be an exceptionally effective anti-theft system, but the mechanism has been abused,” Kunisawa said.

The NPA said it is difficult to grasp the entire picture of damage caused by relay attacks because such thefts rarely leave evidence, such as broken glass and picked doors.

The agency has asked automobile manufacturers to take preventive steps.

Some are taking action, but others have only said they are collecting information.

Although car owners are largely left to fend for themselves against relay attacks, there are some things that can thwart thieves.

M’z SPEED, an automotive supply store in Higashi-Osaka, sells pouches that block electronic key fob signals. The store sold 2,000 pouches in about a month.

Security experts also recommend using “power saving mode” on the key fob, which prevents electronic signals from being sent.

(This article was written by Ken Hasegawa and Shogo Mitsuzumi.)