Computer Virus spreads to Humans

Anti Virus Software

One area where clients seek my opinion concerns anti-virus software. They want a simple answer, which one do I recommend? Like many computer questions, this answer isn't simple. The obvious measure is how effective the product is in spotting known and unknown viruses. Another measure is how easy is it to use. Another aspect is how intrusive it is and how much it slows down your computer.

One of my favorite recommendations is Avira. I like it because it is free, and because it is probably the best or second best (even though it is free!) at finding worms and trojans. The downside to Avira is that it has false positives. AVG doesn't have this problem, and it is easy to use, and free but it isn't as effective as Avira in spotting new viruses. Nod32 excels in both areas, but it isn't free. Norton AV is almost as effective as Avira and Nod32 at detecting viruses, but my experience is that it slows down the computer significantly, and can get corrupted and mess up Windows. The pay version of Avira has an anti spyware component. If you are careful not to download stuff, then you probably don't need anti-spyware software. If you aren't sure or if you do download stuff, I recommend Sunbelt's Counterspy. For $20 it is far superior to the free anti spyware, such as Adaware.

Downloads

Avira Nod32 Counterspy

Below are the different types of malware that can infect your computer. Interestingly the virus types refer to how they get into your computer rather than what they do when they get there.

Traditional Viruses - These add computer code to legitimate software, or to boot sectors on your computer's hard disk. They get transmitted by infecting copies of software that could move to another computer. Since the Internet, people rarely move software from one computer to another, and this old style of virus is rarely a problem anymore. Although boot sector type viruses could again become a big problem.

Root Kit - a root kit is a virus that gets control before Windows loads, and can be very dangerous. This is because Windows is never aware that it is running underneath a root kit's control. It is hard to detect root kits, and since the root kit can have as much control as it needs, its threat is infinite. One way a root kit could get into a computer is with a boot sector virus. Another way is when USB flash drives have code that runs when they are inserted. Sony infamously introduced root kits into Windows computers in 2005 by putting the code into music CDs (these have since been recalled after a lawsuit).

Trojans - This virus gets on your computer pretending to be something else. Opening an email attachment is one way to get this. Downloading free software is another.

Worms - This one infects your computer by drilling directly from the host computer into your computer through the Internet. A firewall will stop this virus, because it makes your computer invisible to the Internet. Since Windows turned on its firewall in 2004, these viruses have become less common.

Spyware - Infects a computer by users who unknowingly download and install it. Either by piggybacking with software the user agrees to install, or by a website installing an activeX control. Spyware's purpose is usually either to deliver ads via pop-ups, toolbars and hijacked web searches - or to track a person's Internet usage, and most nefariously even keys typed. Spyware is usually more difficult to remove than the other types of viruses.

Cookies - Cookies are not dangerous. They are used by websites, to keep track of who you are, and where you are on a website. This is how Yahoo knows who you are for example. Cookies are also used by the bad guys, but by themselves, do not present problems for computers.