What is the ruling on using open Wi-Fi networks of unknown origin for browsing, and is it permissible to use them for downloading if it does not affect their owners?

It is not permissible to benefit from internet lines and networks except with genuine or customary permission from their owner, based on the hadith: "The wealth of a Muslim person is not lawful unless given with a willing soul." Whether this utilization affects the line or not, the fundamental principle is that these lines are private, and it is not permissible to access them without permission.