Virus!

Viruses come in many shapes and forms; from programs that harm personal data on your computer to pieces of code that steal bank passwords or send nuisance emails to everyone in your address book.
Some examples are given below:

Viruses

Are normally small programs that ‘attach’ themselves onto other files on your computer. They usually have ".exe" or ".com" or ".bat" extensions. They can be spread via Email attachments and downloads from the internet. Regardless of what the virus says or does, they are bad to the bone.

Malware

General term for any type of virus, spyware, root kit, backdoor, Trojan or adware.

Worms

Use a network (LAN or internet) to spread themselves. They appear as links (in instant messengers or emails) to virused/infected websites. They often forward themselves to people in your contacts list.

Adware

A type of software which is normally loaded into your computer by advertising companies without your knowledge or consent. This software is responsible for pop-ups on your system, re-direction to a different webpage from the one you were expecting, alteration of your homepage etc.

Spyware

Software which is loaded onto your computer without your knowledge or consent. This software gathers information about you, your computer, your finances, the software you run, who owns the system, the websites you visit etc and ‘reports’ it back to where the software came from (advertising agencies, marketing groups, corporations etc).

Key logger

This type of software records what keys you type, and then sends that information to its owner (hacker, scammer). This is in common use by fraudsters to steal your banking details.

Trojan Horses

A trojan is a program that pretends to be something that it is not (virus scanner, screensaver, music clip etc) but in fact is a malicious file which can in turn download more malware to your machine. These are sometimes present in chatrooms as a link to an image or video - as I found out the hard way. The link to the file appears in a conversation like this: “ lol check out this cool photo ‘http://www......’”. If the user clicks on the link, it will not be a picture that gets downloaded - it may be a virus instead.

This isn't to say that every link in an instant messenger program is a virus (ie: if you recognize the site like "http://youtube.com/watch?v=742uUWqB9AY", but be wary of things like "http://youtube-files.com/watch?v=742uUWqB9AY").

Spam

Unsolicited bulk-sent Email. Basically, just random junk (ie: offers for Viagra, cheap Rolex watches, DVDs, condoms, stock tips, beauty products, get-rich-quick schemes etc). This is generally not harmful, but very annoying.

Some common computer symptoms of having an infection include:
Computer running slower than normal
Computer emits random sounds/warning messages
Error messages are displayed frequently
File loss/data corruption
Applications frequently crashing
Being redirected to different web pages
Anti-virus software malfunctioning
Messages that appear to be from you sent to other people's MSN/Email accounts.
Alteration of your homepage

Safe Web Surfing

Be aware: when browsing some websites (ie: video-sharing sites, entertainment or adult websites) there may be pop-ups and/or banners which claim that your computer has an error or a virus - and a message says “click here for a free scan”. Quite often, these are links to viruses, Trojan horses, adware etc - even if the banner claims to be giving access to a program that removes these.
Also, beware of ".exe", ".bat" or ".com" files that try to download to your machine claiming that they will remove a virus - especially if you have not clicked to initiate the download.

Other messages that you should be careful about are: “you have won a laptop” “shoot 10 ducks & get a free iPod” “you have won our hourly prize!” ...

Remember: things to watch out for include links in a chatroom which look like: “is this you in this picture? http://www........”

Social Networking

Although social networking is a great way to chat and share photos, videos, music etc, it's also a breeding ground for hackers trying to get into your account. Have you ever seen messages that seem to have been posted by you that weren't?
If you have, then it's possible that someone has your account details.

What I would suggest for this would be:
Log out of Myspace or whatever
Wipe your cookies and temporary internet files on your computer
Then open www.myspace.com/facebook.com etc and change your password
Then log out again
Then enter your login details into the site's main page and click "Remember me", then click to login.

After doing this, if you ever click on a myspace link - only for a screen saying "You must be logged in to do that..." to come up, then it is likely to be fake as you have already selected the "Remember me" option. Even though it may be genuine sometimes, if you are in any doubt, go to www.myspace.com and re-enter from there.
(This is only what I suggest from personal experience, I'm not a Myspace official.)
EDIT: Myspace has since installed a safer link system into their site - but caution should always be taken.

Sometimes websites (of ill repute and dodgy quality) or infected links attempt to install an executable file (.exe) on your computer, under the pretence of being a movie, a photo or a media player plug-in/active X control to allow a movie (etc) to be played. Just ask yourself: "If they wanted people to watch their videos, wouldn't they use a standard format like MPEG, Flash or WMV instead of a format which no-one has ever heard of and which requires other things to be installed?" If you ever click on a link believing it to be a movie, sound clip etc and a message pops up saying "You have chosen to download..." and the message contains ".exe" as part of the filename, just click the "Cancel" button.

Bebo

"http://youtube-spy.5x.pl" & "http://youtube-files.bo.pl" may look legit, but just because they contain the word "youtube", that doesn't mean they have anything to do with Youtube.
Avoid clicking these at all costs.

Instant Messengers

The links to viruses that are going through instant messengers (similar to the one shown below) open your default internet browser and direct you to an infected webpage which uses JavaScript, Java or similar to install a virus or Trojan etc onto your computer. Many internet browsers such as Firefox, Netscape or even IE provide you with the option to disable JavaScript and/or Java (usually in the "tools" & "options" menu, or in "quick preferences") - thus reducing the chance of receiving a virus.
Note; With JavaScript and/or Java disabled, some websites may not run correctly (like mine for example). Remember, JavaScript and Java are only bad if they are programmed in an evil way, they are nice most of the time (they are nice all the time on my site).
An alternative is to use Firefox with the Noscript plug-in (mentioned below) - this will only allow JavaScript & Java to run if you say so.

DO NOT OPEN THE LINK DISPLAYED IN THE FOLLOWING PICTURE - This is a screendump of a link to a virus/Trojan horse.

Note that the links may look like a picture file, but only the bit before the "?" will work, possibly downloading a virus.

These links are not always bad, but to be safe, just don't click on any links unless you know & trust the site.

File types

A movie file may have an extension of ".wmv", ".avi", ".flv", ".ogv", ".mov" or ".mpg" etc.
A music file may have an extension of ".wma", ".mp3", ".wav", ".mp4", or ".ogg" etc.
An image file may have an extension of ".jpg", ".bmp", ".png" or ".gif" etc.
An executable program may have an extension of ".exe", ".bat", ".com" or ".sys" etc.
Warning: Files that have the extension ".swf" are called 'Flash movies' - these are commonly found in webpages and are normally harmless - but caution should be exercised if (for example) you receive one as an attachment.

Movies/music/images/Flash movies need to opened with another program (media player, web browser, image viewer etc), whereas executables can open on their own.
If you receive an email with an attachment - which has an executable extension ^{(see above)}, chances are it's a virus.
Even if the message says it's a video or whatever, and especially if it's called something like "funnyvid.mpg.exe" - it's a virus.
Remember: A file can only be of one type, and therefore only have one true extension.
If someone wanted you to watch a video that badly, then they would use a standard video file format (.wmv, .mpg, .mov etc).

Another thing to watch out for is the size of the file:
Executable malware is generally quite small - about 40kB or so (however, this is not set in stone).
So if a video is only around 40kB, it's fake as no video could ever be that small (a 40kB video would last about 0.1 of a second).

Fake Anti-virus

There are some websites out there that claim your computer is infected - and that you should download the site's "free" antivirus program (which in reality is a virus/trojan/key logger itself 99.9% of the time) - which will end up asking you for money or harming your data.
Just because a pop-up message on the net says your computer is infected, that doesn't mean that it is. See below:

As you can see from the images below, a "virus scanner" that goes by the name of AntiVirus 2009 & looks like Windows Explorer (especially if you use Windows Internet Explorer) is telling us that the computer in question is infected and that you must download an AV program.
Just because it looks like Windows & says your PC is infected, that doesn't mean that it is.
If you ever come across this, close the tab (or CTRL-ALT-DEL it and shut the browser down if you can't close the page) - DO NOT DOWNLOAD ANY FILES FROM THE SITE.

Image 1 Image 2 Image 3 Image 4

Legit Anti-virus Programs

Applications such as Symantec Norton, AVG, McAfee, F-Secure and Kaspersky can scan your computer for viruses, root kits, malware, Trojan horses and worms - and remove or quarantine them.
Operating Systems such as GNU/Linux, BSD and Macintosh have much fewer chances (virtually nil) of catching viruses than Microsoft Windows.
If you use Mac & still want to protect yourself, there's a nifty little app called ClamXav. (If you want to be all noble and prevent the passing on of malware to Windows users.)

To scan for and remove spyware or adware you will need an anti-spyware application; such as Microsoft antispyware or Spybot S&D etc.
There are many applications to rid your computer of malware - but you don't need them all.

If you are concerned about your Windows-based machine becoming infected there are a number of ways to protect yourself:
• Switch to an operating system such as Mac or Linux...

Less extreme methods include:
• Switching your unsafe Internet Explorer with the safer Mozilla Firefox
• Installing the Noscript Plugin for Firefox which will block attempts to hijack your machine.
• Downloading the free AVG Antivirus software package.
• Using the McAfee-Avert Stinger application.
• Using the CCleaner application to clean the crap off your machine (that’s what the "C" stands for).


P2P/torrent users may wish to:
• Use Peerguardian (Windows/Mac)
• Use Moblock (Linux)