Fiat Chrysler has decided to recall 1.4 million cars in the US, after security researchers showed that one of its vehicles could be hacked.

On July 21, hackers had taken control of a Jeep Cherokee via its internet-connected entertainment system, tech magazine Wired reported.

Chrysler said it was issuing a voluntary recall to update the software in affected vehicles.

The company added that hacking its vehicles was a “criminal action”.

Fiat Chrysler said exploiting the flaw “required unique and extensive technical knowledge, prolonged physical access to a subject vehicle and extended periods of time to write code” and added manipulating its software “constitutes criminal action”.

The carmaker said it was “unaware of any injuries related to software exploitation”.

It said the recall was issued to help customers with the “ongoing software distribution that insulates connected vehicles from remote manipulation”.

The issue affected up to 1.4 million vehicles sold in the US, which had been fitted with the company’s uConnect system.

The attack was accomplished using relatively cheap off-the-shelf components connected to a laptop, to create a DAB station that broadcast the malicious data.

The Fiat Chrysler recall comes soon after two senators introduced a bill to call on the US Federal Trade Commission and the National Highway Traffic Safety Administration to set standards on vehicle security for car makers.

The bill would also create a security rating system for cars so consumers would know which ones worked hardest to make unhackable cars.

Affected vehicles:

• 2013-2015 MY Dodge Viper specialty vehicles
• 2013-2015 Ram 1500, 2500 and 3500 pickups
• 2013-2015 Ram 3500, 4500, 5500 Chassis Cabs
• 2014-2015 Jeep Grand Cherokee and Cherokee SUVs
• 2014-2015 Dodge Durango SUVs
• 2015 MY Chrysler 200, Chrysler 300 and Dodge Charger sedans
• 2015 Dodge Challenger sports coupes