In general, an infection from either a virus or spyware must be "executed" in some form..That can be done in a number of different methods. Peer-to-Peer (P2P) file sharing networks, such as KaZaa, Morpheus, etc. allow the user to share files with the "world" and as such, it becomes a risky proposition. A file downloaded from such a network, generally, must be opened in order to "execute". A "good" antivirus program should detect the embedded malware DURING the download process but it's not a guarantee. Unfortunately, compressed files, such as .zip and .rar files can frequently mask the malware that they contain. Therefore, scanning with your onboard antivirus is always a good idea. Even safer...DON'T USE P2P file sharing programs..
Another avenue of infection...., various "bad" websites may contain ActiveX controls and "scripting" exploits that will immediately "execute" and install malware immediately upon visiting the site. Browser vulnerabilities cause this to happen so it's best to "harden" your browser by securing it's settings or use a browser that is more secure to start with. In this case, your antivirus and spyware "background" scanners will need to be operational to detect the incoming malware.
Another method of infection is through e-mail. Antivirus background scanners need to be functioning correctly to detect this type of potential infection. Leaving the "Preview Pane" enabled in Outlook and Outlook Express can automatically "execute" attachments contained in the message and immediately infect the machine. TURN OFF the "Preview Pane" to stop this type of automatic execution. It's a good idea to scan ALL incoming attachments to verify that they're safe...and DELETE all message from unknown senders.
Hope this helps.
I have a Dell Dimension 4700C.The operating system is Microsoft Windows XP Professional. I have the Norton Internet Security 2005 AntiSpyware Edition and a Microsoft Firewall.Would you illustrate the dynamics of a computer viral infection process. Obviously, I'm a layman but I think that if I know what I'm looking for, I can protect my computer. Specifically, David T, responding to Gretchen G's concerns about using "KAAZA", cautions:
'Be careful of what you download and think if it seems reasonable: there are few software programs out there under 100 kilobytes, but plenty of viruses and worms fit the category.'
That seems to suggest that the typical virus will stand out because of its small size. Am I close?
Another caution states:
'Scan all files you download immediately.'
I always thought the viruses got in as part of the downloading process. If that's the case then isn't your scan too late?