Originally Published: 14 FEB 23 12:30 ET

Updated: 14 FEB 23 17:38 ET

By Peter Valdes-Dapena, CNN

(CNN) -- Hyundai and Kia are offering a new free software patch to owners of 8.3 million vehicles that are so easy to steal that some insurance companies refuse to offer coverage for them in certain markets.

The vehicles in question, 2015-2019 Hyundai and Kia models with turn-key ignitions — as opposed to push-button start — are roughly twice as likely to be stolen as other vehicles of a similar age. The reason: Many of these vehicles lack some of the basic auto theft prevention technology included in most other vehicles, even in those years, according to the Highway Loss Data Institute.

The models in question don't have electronic immobilizers, which rely on a computer chip in the car and another in the key that communicate to confirm that the key belongs with that vehicle. Without the right key, an immobilizer should do just that — stop the car from moving.

These models became the subject of a social media trend in which thieves filmed themselves and others stealing Hyundai and Kia vehicles and took them on joyrides. Thefts of these vehicles resulted in at least 14 crashes and eight deaths, according to the National Highway Traffic Safety Administration.

The two South Korean automakers have come up with a software patch to fix the problem, the automakers and NHTSA said Tuesday. Hyundai and Kia operate as separate companies in the United States, but Hyundai Motor Group owns a large stake in Kia, and various Hyundai and Kia models share much of their engineering.

The patch will be installed free of charge on vulnerable models, with software that requires an actual key in the ignition to turn the vehicle on. (Thieves have been using the tips of USB cables to turn the ignition switch) The software will also block the car from being started after the doors have been locked using the key fob remote control. The vehicle will need to be unlocked before it can be started. The software also extends the length of the alarm sound from 30 seconds to a full minute. Hyundai dealers will also affix window stickers stating that the vehicle has anti-theft software installed.

Hyundai will begin providing the software immediately for the most popular — and most frequently stolen — vulnerable models. Kia said it has started to offer the update to some customers and expects to make it available to affected vehicles "over the next few months."

Correction: An earlier version of this story misstated when Kia's software would be installed.