Polar M400

Security Evaluation

1. Device Security

Criterion	Value	Proof	Comment
Known hardware tampering	Rare	https://github.com/rsc-dev/pbd 🔗 Proof
Known vulnerabilities	None	—
Prior attacks	None	—
Updatability	Rare	[ last firmware update in 2019, the app is updated 🔗 Proof]
Category Score	Score: 2 / 3

2. System Security

Criterion	Value	Proof	Comment
Authentication with other systems	Full	via the polar flow app or web service 🔗 Proof
Communications	Encrypted with up-to-date encryption	🔗 Proof
Storage	Encrypted with up-to-date encryption	🔗 Proof
Category Score	Score: 1 / 3

3. User Authentication

Criterion	Value	Proof	Comment
Account management	Absent	—
Authentication	Absent	—
Brute-force protection	Absent	—
Event logging	Partial logging	—
Passwords	Default/Common/Easy to guess	—
Category Score	Score: 3 / 3

Technical Specifications

Property	Details
Operating System & App	custom (Companion App: )
Hardware (CPU / GPU)	CPU: • GPU:
Memory & Storage	Memory: • Storage:
Power, Battery & Charging	Battery: 190 mAh Li-pol rechargeable battery • Power: • Charging: usb
Display & Camera	Display: • Camera:
Sound & Connectivity	Sound: • Connectivity: micro-USB - bluetooth - GPS
Physical (Dimensions & Mass)	Dimensions: 11.8 x 9.8 x 7.4 cm • Mass: 54.4 g

The watch only store the data during training and isn't always connected with internet. You can sync your data via usb or bluetooth with the Polar Flow app. It has been shown that it is possible to extract sensitive information from the polar flow app (See https://www.bellingcat.com/resources/articles/2018/07/08/strava-polar-revealing-homes-soldiers-spies/).

additional links : https://support.polar.com/e_manuals/M400/Polar_M400_user_manual_English/Content/Technical-Specifications.htm https://support.polar.com/e_manuals/M400/Polar_M400_user_manual_English/manual.pdf