LAS VEGAS — A hacker has discovered a way to force ATMs to disgorge their cash by hijacking the computers inside them. The attacks demonstrated Wednesday targeted standalone ATMs. But they could potentially be used against the ATMs operated by mainstream banks.
There are many types of attacks in use today, ranging from sophisticated to foolhardy: installing fake card readers to steal card numbers, hiding tiny surveillance cameras to capture PIN codes, covering the dispensing slot to intercept money and even hauling the ATMs away with trucks in hopes of cracking them open later.
Computer hacker Barnaby Jack spent two years tinkering in his Silicon Valley apartment with ATMs he bought online. These were standalone machines, the type seen in front of convenience stores, rather than the ones in bank branches.
His goal was to find ways to take control of ATMs by exploiting weaknesses in the computers that run the machines. He showed off his results here at the Black Hat conference, an annual gathering devoted to exposing the latest computer-security vulnerabilities.
Jack, who works as director of security research for Seattle-based IOActive Inc., showed two ways he can get ATMs to spit out money:
Jack found that the physical keys that came with his machines were the same for all ATMs of that type made by that manufacturer. He figured this out by ordering three ATMs from different manufacturers for a few thousand dollars each. Then he compared the keys he got to pictures of other keys, found on the Internet.
He used his key to unlock a compartment in the ATM that had standard USB slots. He then inserted a program he had written into one of them, commanding the ATM to dump its vaults.
Jack also hacked into ATMs by exploiting weaknesses in the way ATM makers communicate with the machines over the Internet. Jack said the problem is that outsiders are permitted to bypass the need for a password. He didn't go into much more detail because he said the goal of his talk "isn't to teach everybody how to hack ATMs. It's to raise the issue and have ATM manufacturers be proactive about implementing fixes."
The remote style of attack is more dangerous because an attacker doesn't need to open up the ATMs.
It allows an attacker to gain full control of the ATMs. Besides ordering it to spit out money, attackers can silently harvest account data from anyone who uses the machines. It also affects more than just the standalone ATMs vulnerable to the physical attack; the method could potentially be used against the kinds of ATMs used by mainstream banks.
Jack said he didn't think he'd be able to break the ATMs when he first started probing them.
"My reaction was, 'this is the game-over vulnerability right here,' " he said of the remote hack. "Every ATM I've looked at, I've been able to find a flaw in. It's a scary thing."
Jack wouldn't identify the ATM makers. He put stickers over the ATM makers' names on the two machines used in his demonstration.
But the audience, which burst into applause when he made the machines spit out money, could see from the screen prompts on the ATM that one of the machines was made by Tranax Technologies Inc., based in Hayward, Calif. Tranax did not immediately respond to e-mail messages from The Associated Press.
Triton Systems, of Long Beach, Miss., confirmed that one of its ATMs was used in the demonstration. It said Jack alerted the company to the problems and that Triton now has a software update in place that prevents unauthorized software from running on its ATMs.
Bob Douglas, Triton's vice president of engineering, said customers can buy ATMs with unique keys but generally don't, preferring to have a master key for cost and convenience.
"Imagine if you have an estate of several thousand ATMs and you want to access 20 or so of them in one day," he wrote in an e-mail to the AP. "It would be a logistical nightmare to have all the right keys at just the right place at just the right time."
Other ATM manufacturers contacted by the AP also did not immediately respond to messages.
Jack said the manufacturers whose machines he studied are deploying software fixes for both vulnerabilities, but added that the prevalence of remote-management software broadly opens up ATMs to hacker attacks.