Malicious Dialer Software

Dialer - Dialing Software: Any program that utilizes a computer’s modem to make calls or access services. Users may want to remove dialers that dial without the user’s active involvement, resulting in unexpected telephone charges and/or cause access to unintended and unwanted content.

Dialers are necessary to connect to the internet (at least for non-broadband connections), but some dialers are designed to connect to premium rate numbers. The providers of such dialers often search for security holes that may be present in the operating system installed on the user's computer and use them to change the computer to dial up through their number, pocketing the additional money for themselves.

Users with DSL lines (or similar broadband connections) are usually not affected. A dialer can be downloaded and installed, but dialing in is not possible as there are no regular phone numbers in the DSL network and users will not typically have their dial-up modem, if any, connected to a phone line. However, if an ISDN adapter or additional analog modem is installed, the dialer might still be able to get a connection.

Malicious dialers can be identified by the following characteristics:

• A download popup opens when opening a website.
• On the website there is only a small hint, if any, about the price.
• The download starts even if the cancel button has been clicked.
• The dialer installs as default connection without any notice.
• The dialer creates unwanted connections by itself and without user interaction.
• The dialer does not show any notice about the price (only few do) before dialing in.
• The high price of the connection is not being shown while connected
• The dialer cannot be uninstalled, or only with serious effort.

Another way of stealing money from the infected PC owner is to take control of the modem and dial an expensive toll call. Dialer or porn dialer software dials up a premium rate telephone number and leaves the line open, charging the call to the infected user.