If your telephone bill was unusually high last month and noticed several unknown international numbers printed on your bill, while nobody in your house would call those numbers, this could mean that you have been modem-jacked.
Here are a few steps to reduce the of modem jacking from happening to you:
Don't Be Lured to View 'Free' Websites
Read the terms and conditions before accessing new websites. Don't click "Submit" or "I Accept" button if there a clause stating customers will be connected to an international dialer or Internet Service Provider (ISP).
Know What Number You Are Dialing To
Before connecting to the internet, reset your dialer to your local ISP of you suspect any past usage resulted in your dialer automatically defaulting to an international ISP connection.
Beware of Pop-up Windows
Some internet adult entertainment websites are designed to attach cookies to other websites you frequently use. Instead of clicking 'X' or 'close' button on the window, press the 'Alt' and 'F4' buttons simultaneously to close the pop-up window.
Hope this could help you to prevent yourself from modem jacking. Bye. :)