Description
This is a trojan detection. Unlike viruses, trojans do not self-replicate. They are spread manually, often under the premise that they are beneficial or wanted. The most common installation methods involve system or security exploitation, and unsuspecting users manually executing unknown programs. Distribution channels include email, malicious or hacked web pages, Internet Relay Chat (IRC), peer-to-peer networks, etc.
Indication of Infection
Presence of the aforementioned registry key and a process named psoft1.exe or ps1.exe in task manager.(* The name of the process may vary this is just an example)
Please note: If Adware is installed via a Downloader it may install it "cleanly" with the relevant uninstaller included for the user to terminate this Adware, although frequently this is not the case.
A snapshot of a severely infested machine
Methods of Infection
N/A. Downloaders are not viruses, and as such do not themselves contain any method to replicate. However they may themselves be downloaded by other viruses and/or Trojans to be installed on the user's system.
Many of these additionally are mass spammed by the author to entice people into double-clicking on them.
Alternatively they may be installed by visiting a malicious web page (either by clicking on a link, or by the website hosting a scripted exploit which installs the Downloader onto the user's system with no user interaction.