Trojan Downloader (generic description)

Trojan downloader is usually a standalone program that attempts to hiddenly download and run other files from remote web and ftp sites. Usually trojan downloaders download different trojans and backdoors and activate them on an affected system without user’s approval. Trojan downloader, when run, usually installs itself to system and waits until Internet connection becomes available. After that it attempts to connect to a web or ftp site, download specific file or files and run them.

Most famous trojan downloaders: Aphex, Dlder, Small, WebDL.