Dialer

A dialer automatically inserts and modifies the numbers depending on the time of day, country or area code dialed, allowing the user to subscribe to the service providers who offer the best rates.

Malicious dialers can be identified by the following characteristics:[citation needed] Computers running Microsoft Windows without anti-virus software or proper updates could be vulnerable to Visual Basic-scripts which install a trojan horse which changes values in the Windows Registry and sets Internet Explorer security settings in a way that ActiveX controls can be downloaded from the Internet without warning.

After this change is made, when a user accesses a malicious page or email message, it can start installing the dialer.

[citation needed] E-mail spam from a so-called "AntiVirus Team" for example, contained download links to programs named "downloadtool.exe" or "antivirus.exe", which are malicious dialers.

Therefore, links in spam emails should never be opened, automatically started downloads should be canceled as soon as discovered, and one should check on each dial-up to the Internet to see whether the displayed phone number is unchanged.

The law contains the following regulations: On 4 March 2004 the German Federal Supreme Court in Karlsruhe decided that fees for the usage of dialers do not have to be paid if it was used without the user's knowledge.