Malware

 
malwarecpm

You may hear in the news about the latest virus, worm or trojan in circulation. Perhaps you've been unfortunate enough to be the victim of one.
Either way, if you want to know more about what they are or what you can do to protect yourself from them then this is the section for you.

 

What Is Malware?


"Mal" is short for malicious and "ware" continues the theme of software (computer programs) and hardware (computer equipment).
Malware covers viruses, worms and trojans. These days the term virus tends to be used to encompass all of these although each is a distinctive type of program.
A computer virus is a piece of code that attaches itself to other code, data or processes to propagate. They used to be spread by infected floppy disks. With the advent of mass email use though email has proven to be a far more effective route of infection.
Worms are self-contained and are able to spread without hitching a ride on something else and without human intervention (such as opening an email).
A trojan (short for Trojan Horse) is a program that masquerades as something useful or entertaining but also contains instructions to do something else behind the scenes. This could be to allow the writer control over your machine (known as opening a back door) or to steal data or passwords but is rarely pleasant or it would not need to be hidden. Back Orifice and SubSeven are among the best known trojans.

How Do I Stop Viruses

How Do I Stop Viruses

 
malwarecpm

There are three forms of defence that together can greatly reduce your exposure to viruses, worms and trojans.
The first type of defence is an antivirus program such as McAfee VirusScan. This is used to scan your email, harddrive and, possibly, downloads for known malware. If a virus scan turns up any infected or malicious files then in most cases it should also be able to disinfect your computer by removing trojans or worms with no other use or cleaning up any files that have been infected with a virus.
There are new viruses, and new versions of old viruses, coming out all the time so it is vital that you keep your antivirus software up to date. Any half-way decent anti virus scanner should have a mechanism for automatic download of new virus definitions over the internet. You should also scan any programs you download from the internet before you run them unless your antivirus program automatically does this.
However, anti virus scanners tend to be best on already known threats. Many will have some functionality to look out for generally suspicious activity from a program but these "heuristics" are far from perfect. Combined with the speed with which some modern viruses, and especially worms, can spread some will inevitably make it past this first line of defence. This is where the second defence against viruses comes into play.

Stop Viruses - Part Two

 
malwarecpm

As discussed in Part 1 while antivirus software is an essential it has its vulnerabilities. It should be complemented by a second line of defence which is something called a firewall.
A firewall acts as a sentry for internet traffic. It works by only allowing certain information to flow between your computer and the internet. Some trojans may set themselves up on your computer in order to listen for instructions being sent to them over the internet. With a firewall in place hopefully those instructions would never reach them.
A firewall can take two forms.
A hardware firewall takes the form of a box that sits between your computer and your internet connection. A hardware firewall is generally the more expensive option but more secure as any attack has to get through this box before reaching your computer.
A personal firewall, such as McAfee Personal Firewall Plus, is a program that runs on your computer performing much the same kind of role as the hardware firewall. It may also be able to allow internet traffic on a per program basis so that if a trojan or worm does sneak on to your computer it will not be able to connect to the internet unless you give it permission to do so.

Stop Viruses - Part Three

 
malwarecpm

While the defenses discussed in parts one and two took the form of hardware or software the third weapon in your defenses against viruses, worms and trojans is common sense.
By taking care over your email and internet use you lessen the risk of catching something nasty.
Part of this is allowing your other two defenses to do their job. Do not turn them off unless you're sure of what you are doing and if you do turn them off then turn them on again as soon as possible. Scan all files and programs that you download from the internet (unless your antivirus software does this automatically of course).
But there are other things you can do that are not dependant on your antivirus programs or firewall.