Researchers gain control of tesla charger Through firmware downgrade

Tesla’s popular Wall Connector home EV charger was compromised at the January 2025 Pwn2Own Automotive competition, revealing how attackers could gain full control via the charging cable.

The Tesla Wall Connector Gen 3, a widely deployed residential AC charger delivering up to 22 kW, was exploited through a novel attack that used the physical charging connector as the main entry point.

The vulnerability allowed researchers to execute arbitrary code, potentially giving access to private networks in homes, hotels, or businesses.

Researchers from Synacktiv discovered that Tesla vehicles can update the Wall Connector’s firmware via the charging cable using a proprietary, undocumented protocol.

By simulating a Tesla car and exploiting Single-Wire CAN (SWCAN) communications over the Control Pilot line, the team downgraded the firmware to an older version with exposed debug features.

Using a custom USB-CAN adapter and a Raspberry Pi to emulate vehicle behaviour, they accessed the device’s setup Wi-Fi credentials and triggered a buffer overflow in the debug shell, ultimately gaining remote code execution.

The demonstration ended with a visual cue — the charger’s LED blinking — but the broader implication is access to internal networks and potential lateral movement across connected systems.

Tesla has since addressed the vulnerability by introducing anti-downgrade measures in newer firmware versions. The Pwn2Own event remains instrumental in exposing critical flaws in automotive and EV infrastructure, pushing manufacturers toward stronger security.

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