The service can install security patches to an idle car and is being tested by luxury automakers Aston Martin and Range Rover.
Macquarie analyst Gus Papageorgiou told his clients that auto security is among several areas that Blackberry is betting will boost its revenue after the Canadian company dropped out of the smartphone race.
However Papageorgiou may have spoken out of turn as Blackberry has denied the story and Matthew Clarke, a spokesman for Aston Martin, said in an email he was not aware of the company testing such a product.
According to Papageorgiou, the service could be launched as early as next year, generating about $10 a month per vehicle for BlackBerry.
Vehicles increasingly rely on dozens of computers that connect to each other as well as the internet, mobile networks and Bluetooth communications systems that make them vulnerable to remote hacks.
Automaker interest in cyber security has risen dramatically since 2015, when two hacking experts uncovered vulnerabilities in Fiat Chrysler vehicles that led to a US recall of 1.4 million autos.