It’s important to know the source of an application. Applications of unknown origins may have malicious code which once installed on your computer, can basically have access to your entire system.
Trusted sources of software include internal applications developed by your own employees, or well known publishers such as Microsoft. Applications are commonly digitally signed so that you know the application actually came from the publisher and the code has not been changed.
Untrusted sources include applications downloaded from third party sites or downloaded from an email, peer to peer downloads from torrent sites, or drive by downloads which are applications that start to automatically download to your system.
