70mai Dashcam M300 Denial-of-Service Vulnerability in Telnet Service

A denial-of-service vulnerability has been identified in the 70mai Dashcam M300, affecting versions through 20250611. The issue arises in the Telnet service, specifically within the demo.sh script, which is executed automatically when Telnet is accessed. This vulnerability requires local network access and has a high attack complexity. Exploitation involves interrupting the default script execution, as failing to do so will cause the dashcam to crash, indicated by a change in the status light from green to blinking blue, then red. The device remains disabled until the battery drains and it reboots.

Impact

Exploitation of this vulnerability causes the dashcam to crash and become disabled, requiring a manual reboot after the battery is drained.

Reproduction

To reproduce this vulnerability, access the dashcam's Telnet service. The demo.sh script will run automatically. To prevent the script from causing a crash, interrupt its execution. If the script is allowed to run, it will lead to a crash, with the dashcam's status light changing from green to blinking blue, then red, indicating a disabled state until it reboots after the battery power drains.

Remediation

It is recommended to firewall the device to block unauthorized Telnet access.