Teens Hacked Boston Subway’s CharlieCard to Get Infinite Free Rides—and This Time Nobody Got Sued

In working with Rauch, the MBTA had created a vulnerability disclosure program to cooperate with friendly hackers who agreed to share cybersecurity vulnerabilities they found. The teens say they were invited to a meeting at the MBTA that included no fewer than 12 of the agency’s executives, all of whom seemed grateful for their willingness to share their findings. The MBTA officials asked the high schoolers to not reveal their findings for 90 days and to hold details of their checksum hacking techniques in confidence, but otherwise agreed that they wouldn’t interfere with any presentation of their results. The four teens say they found the MBTA’s chief information security officer, Scott Margolis, especially easy to work with. “Fantastic guy,” say Bertocchi.

The teens say that as with Rauch’s cloning technique, the transit authority appears to be trying to counter their technique by detecting altered cards and blocking them. But they say that only a small fraction of the cards they’ve added money to have been caught. “The mitigations they have aren’t really a patch that seals the vulnerability. Instead, they play whack-a-mole with the cards as they come up,” says Campbell.

“We’ve had some of our cards get disabled, but most get through,” adds Harris.

So are all four of them using their CharlieCard-hacking technique to roam the Boston subway system for free? “No comment.”

For now, the hacker team is just happy to be able to give their talk without the heavy-handed censorship that the MBTA attempted with its lawsuit 15 years ago. Harris argues that the MBTA likely learned its lesson from that approach, which only drew attention to the hackers’ findings. “It’s great that they’re not doing that now—that they’re not shooting themselves in the foot. And it’s a lot less stressful for everyone,” Harris says.

He’s also glad, on the other hand, that the MBTA took such a hardline approach to the 2008 talk that it got his attention and kickstarted the group’s research almost a decade and a half later. “If they hadn’t done that,” Harris says, “we wouldn’t be here.”

Update 5 pm ET, August 10, 2023: Added a statement form an MBTA spokesperson.