Cyber Security researchers are pushing back against Chrysler for mitigating the Jeep vulnerability by mailing a USB drive and hoping customers will plug it in to their vehicles to fix the known problems:

Security pros have long warned computer users not to plug in USB sticks sent to them in the mail—just as they shouldn’t plug in thumb drives given to them by strangers or found in their company’s parking lot—for fear that they could be part of a mass malware mailing campaign. Now Chrysler is asking consumers to do exactly that, potentially paving the way for a future attacker to spoof the USB mailers and trick users into installing malware on their cars or trucks.

“An auto manufacturer is basically conditioning customers into plugging things into their vehicles,” says Mark Trumpbour, an organizer of the New York hacker conference Summercon whose sister-in-law’s husband received the USB patch in the mail Thursday. “This could have the potential to backfire at some point in the future.”

When WIRED reached out to Chrysler, a spokesperson responded that the USB drives are “read-only”—a fact that certainly wouldn’t protect users from a future spoofed USB mailing—and that the scenario of a mailed USB attack is only “speculation.”

While the idea of mailing out a USB drive is not the best method, it likely is the only mechanism Chrysler has in its current arsenal. In the future they need to devise a much more secure method to release these types of security updates.