Millions of cars could be tracked and unlocked by a hidden security flaw

## Executive summary Researchers found that KARR aftermarket Bluetooth car alarms share a plaintext authentication key in the companion app, allowing an attacker within ~5 yards to unlock vehicles, disable ignition, trigger alarms across multiple cars, and use broadcast identifiers to track vehicle locations; about 2.2 million vehicles are affected and roughly half of owners may be unaware and unpatched.