Trojans are not viruses! Viruses self-replicate and spread themselves throughout computers and networks on their own accord and wherever they can.
Trojans are spread manually, via links or activation buttons for example.
You may receive an email, read an article on a malicious website or attempt to download some software. Perhaps even click on something you see on an internet chat site.
Once you have 'clicked' on either and you have given permission for the software to run on your computer, you allow the trojan to set to work on compromising your system.
What usually happens next is the Trojan will start writing to your computers' registry, which contains all of your systems' information and settings.
Ever installed some software that you actually wanted? Well each time you do, the same thing occurs except your putting things there that you need for your favourite browser or media player to work.
Some of the things that get put into the registry include user names and permissions, and file locations so that your computer knows where to find the right files. For example, a media plug-in for your browser to play your music while you browse.
So, when a trojan infects your registry, it can place some information there that can track your browsing and the registry entry contains no information for changing permissions.
Have you heard of the latest 'do no track' setting that all new browsers now have?
Well imagine the same thing, but you don't have a little check box to stop it tracking all your internet activity.
So, here's where your anti-virus software does the work you've paid for.
Assuming the company that's made your anti-virus software is aware of the latest threats, after updating to the latest scan engine it should find the threat and either remove the entire infection, or most of it, leaving the rest to be removed manually.
You will usually find instructions on the anti-virus software makers website on how to remove what, if anything, that's left over on your pc. So, how do you avoid being infected in the first place?
Here are a few helpful tips:
- Avoid suspicious looking sites that seem to be asking for personal information where there is no apparent reason as to why it's needed.
-If a link or image (link) looks suspicious, ignore it!
-Ensure that you keep your anti-virus software up to date and use one with a real-time scan which continually monitors the software on your computer and alerts you of any suspicious attempts to access your pc.
-Scan your computer for infections regularly. Set up a scan schedule to run daily or weekly, perhaps depending on how often you use the computer and access the internet.
-If other people use your computer, let's say the rest of the family, use parental controls to minimize the potential of accessing malicious websites.
-Use some common sense. If the website you've just arrived on looks a little like they want you to 'click here' over and over. It's probably best to leave.
-Use browser security add-ons like AVG or McAfee safe search. They keep a database of malicious sites and links, or sites that haven't been assessed yet.
-Always keep in mind that there are people out there that want to infect your computer, do everything you can to stop it. Don't assume that the security on your computer can run itself automatically all day every day. Check it yourself!