What is a zombie computer?
A zombie computer, also known as a bot, is a computer that has been infected by a malware, often a trojan, allowing an attacker to take control of the compromised PC and use it to serve malicious purposes like sending spam, hosting illegal websites or launching DDoS attacks.
DDoS (Distributed Denial of Service) attacks are launched with the aim of crashing a server by flooding it with packets of data. DDoS attacks are effective and dangerous because the traffic can rise from hundreds of thousands of zombies; users are not even aware that they participate at an attack. Imagine your server being bombarded by so much zombies!
Those who are not worried should reconsider their position: an expert estimated that zombie networks count between one million and two million infected machines! And, each day, this number increases dramatically! Yours could really be in!
Another side effect of zombie networks: SPAM!
Who never received spam in their email box? Did you ever wonder why spammers almost never get arrested? Reasons are numerous; however, remember that they often use stolen resources, such as zombie computers, or get protected by corrupt Internet service providers (ISPs) in some foreign countries. That, and many other tricks to obfuscate their traces, makes it a challenge to catch them.
My personal privacy could be at risk?
In fact, not really. Contrary to popular myth, most of attackers are not interested in your latest secret trip with your boyfriend; what they want is your Internet bandwidth and sensitive data like your passwords to commit their crimes!
Maybe you ask yourself: “I have no important accounts and I don’t care about my bandwidth being stolen. So, what’s the deal?”
Hypocrite and selfish question: on the Internet, what you do affect everyone. And, as you can see, botnets are a major danger poisoning the entire network. Will you let a complete stranger “borrow” your car for a hold-up? No. Same goes for your computer.
My computer is fine; it’s not slow at all!
Attackers do not want you to know that your machine fell under their control. Yet, if you are severely infected, you can notice symptoms like unwanted pop-ups, hijacking of your browser, slow-downs, etc.
In all cases, be sure to scan your computer every week with an anti-virus and an anti-spyware. Do not forget a firewall or you will be infected in less than 30 minutes.
It is possible to avoid being infected?
Sure thing! Spend a bit of time to learn how to use a computer; scan emails, web pages, downloads and your hard drive for nasty stuff; resist the temptation to revise your human anatomy on doubtful sites; think before clicking and you should be in business!
If you do not put the effort, you will get infected each time.