Prevent Modem Hijacking

Published 27/07/2004 09:48   |    Updated 13/02/2009 13:09
What can I do to about Modem Hijacking software?

There are a number of scams on the Internet that customers should be aware of. Some of which can result in large telephone bills. “Modem Hi-Jacking” or “Mini -Diallers” are the terms used to describe one such scam.


Modem Hi-Jacking occurs when a website you are visiting purposely disconnects you from your chosen Internet Service Provider and reconnects you to the Internet through an international or premium rate number. These websites will usually provide premium content such as pornographic material, shareware, music, children’s games, ring tones and movie clips.


When the website is accessed, a large number of pop-up windows will appear. You may be asked to install some software or accept the Terms & Conditions of the site, to facilitate the downloading of that content. This process may install a dialler on your computer that will replace your default Internet connection with one that dials a premium rate telephone number or an international telephone number, which can be charged at up to €5.00 per min. There will be a prompt for you to accept the changes. However, this may not always be clear, as it may be in small print amongst other information on the website.


The owners of these sites may have the dialler software integrated into their web page code to automatically download and install onto a user’s computer. The idea behind these programs is that the people who produce them are able to generate revenue from users who dial into the number installed from the web page.


If you are a broadband user you will not be affected by this, as long as you have disconnected the internal dial-up modem from your phone socket and don't use this modem to make fax or voice calls.


Top Tips:

  • Avoid going to sites of questionable content.
  • If you accidentally stumble onto one of these sites, close down any pop-up windows that open.
  • Users should not download and/or install any software from sites where there are large volumes of pop-up windows.
  • Read everything before clicking OK, especially when you are going to download something.
  • Ensure the computer is configured to reject Active X Scripts. Ensure that the browser on your computer is left at the default security setting.
  • Keep your operating system patched with the latest upgrades from your software's manufacturer. For further help with this contact your operating system's manufacturer.
  • Call your telephone service provider (not your ISP) and bar international and premium rate calls on the telephone line used to connect to the Internet.

  • Turn off your computer and modem when not in use.
  • Do not delete data from your browser's history files, so that you can trace back problems if necessary.
  • Make sure you can hear your modem. Some people have a volume control on their modem and have it turned down - and so cannot hear it re-dialling.
  • Be aware of the icons on your desktop and ensure that no new icons have appeared that you have not installed or downloaded.
  • Review your network and dial-up connections and remove any connections that you are not familiar with, and verify the phone numbers that are being dialled.
  • Always check your telephone bill.


For more information on Modem Protection software from BT that will help guard against your computer and phone bill being hijacked, please visit -

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