This type of trojan contains one or more malicious programs, which it will secretly install and execute.
Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.
Very often on-line advertisement companies use Trojan-Droppers to silently drop their adware/spyware components or downloaders to users' computers. It is recommended to scan an affected computer with an antispyware program, or an antivirus program with antispyware capabilities. There also exist several good third-party utilities to clean adware/spyware components and downloaders from infected computers.
A Trojan-Dropper is a type of trojan that drops different type of standalone malware (trojans, worms, backdoors) to a system. It is usually an executable file that contains a other files compressed inside its body. When a Trojan-Dropper is run, it extracts these compressed files and saves them to a folder (usually a temporary one) on the computer.
In many cases, Trojan-Droppers also drop and executes to display games, images or messages, which serve as decoys to avert attention from malicious activities.
For representative examples of Trojan-Droppers, see the following descriptions:
Some Trojan-Droppers extract components directly to memory and activate them there. In this case anti-virus software is not able to detect dropped malware, so detection of the whole trojan dropper package is added.
For more information, see Terminology: Trojan-Dropper.