User manual

Viruses and more
Avira Free Antivirus - User Manual (Status: 16 Dec. 2013) 180
Backdoor Clients
In order to steal data or manipulate computers, a backdoor server program is smuggled in
unknown to the user. This program can be controlled by a third party using backdoor
control software (client) via the Internet or a network.
Your Avira product recognizes "Backdoor control software". If the Backdoor control
software option is enabled with a check mark in the configuration under Threat categories,
you receive a corresponding alert if your Avira product detects such software.
Dialer
Certain services available in the Internet have to be paid for. They are invoiced in
Germany via dialers with 0190/0900 numbers (or via 09x0 numbers in Austria and
Switzerland; in Germany, the number is set to change to 09x0 in the medium term). Once
installed on the computer, these programs guarantee a connection via a suitable premium
rate number whose scale of charges can vary widely.
The marketing of online content via your telephone bill is legal and can be of advantage to
the user. Genuine dialers leave no room for doubt that they are used deliberately and
intentionally by the user. They are only installed on the user’s computer subject to the
user’s consent, which must be given via a completely unambiguous and clearly visible
labeling or request. The dial-up process of genuine dialers is clearly displayed. Moreover,
genuine dialers tell you the incurred costs exactly and unmistakably.
Unfortunately there are also dialers which install themselves on computers unnoticed, by
dubious means or even with deceptive intent. For example they replace the Internet user’s
default data communication link to the ISP (Internet Service Provider) and dial a cost-
incurring and often horrendously expensive 0190/0900 number every time a connection is
made. The affected user will probably not notice until his next phone bill that an unwanted
0190/0900 dialer program on his computer has dialed a premium rate number with every
connection, resulting in dramatically increased costs.
We recommend that you ask your telephone provider to block this number range directly
for immediate protection against undesired dialers (0190/0900 dialers).
Your Avira product can detect the familiar dialers by default.
If the option Dialers is enabled with a check mark in the configuration under Threat
categories, you receive a corresponding alert if a dialer is detected. You can now simply
delete the potentially unwanted 0190/0900 dialer. However, if it is a wanted dial-up
program, you can declare it an exceptional file and this file is then no longer scanned in
future.
Double Extension Files
Executable files that hide their real file extension in a suspicious way. This camouflage
method is often used by malware.