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Zombie (virus) – definition and meaning

A zombie virus gains access to a computer or smartphone system through the Internet and takes control of its resources. It uses the infected computer as its launch-pad – sending viruses, Trojan horses, or malicious data to other systems. While the virus and the harm it creates spreads, the original perpetrator’s identity remains hidden.

In the world of IT (information technology), the infected computer is known as a zombie computer. The perpetrator typically uses the infected computer to carry out illegal activities.

The computer user, in virtually every case, is completely unaware that his or her device and systems have been taken over.

Even though the infected computer is compromised, it can still be used. Sometimes, after becoming infected, it might slow down slightly. However, not enough for the user to notice.

Zombie virusThe zombie virus infects other computer systems, smartphones, and electronic communication devices through the Internet. Zombies may have colossal armies of more than one million infected computers across the world.

Compromised computers are metaphorically compared to fictional zombies because their owners are unaware that they are infected.

When a infected computer starts sending out hundreds of thousands or even millions of spam messages, or begins attacking specific web pages, it and its owner become the focal point of cyber-security investigators.



If a zombie virus infects your computer, you may suddenly find that your ISP (Internet Service Provider) has cancelled your service. You may eventually discover that you are being investigated as a suspected criminal.

Some zombie armies are huge

As soon as your device is located and neutralized, the perpetrator continues, using the many other infected computers under his or her control

The perpetrator of the zombie virus, the person guilty of infecting the victim computers, is often referred to as the cracker.

SMS worm - zombie virusIf a smartphone user is fooled into clicking on a link embedded within an SMS, and if their phone is unprotected, the virus will install itself in the phone. It will then try to send text messages to the first ten, twenty or thirty contacts. Soon, tens of thousands of smartphones are infected.

According to Computer.HowStuffWorks.com:

“One investigation allegedly discovered that a cracker’s single computer controlled a network of more than 1.5 million computers.”

In an article published in PC World in 2005‘Spam Slayer: Slaying Spam-Spewing Zombie PCs’ – Tom Spring wrote than an estimated fifty percent of all spam that year came from zombies – a 25% increase over the previous year.



DDOS attacks and zombie viruses

Zombie viruses are often used to conduct DDOA (distributed denial-of-service) attacks. DDOS attacks involve the orchestrated flooding of targeted websites. The website gets a massive number of simultaneous visitors – infected computers – so many that the whole system crashes.

A distributed degradation-of-service attack is a variant of a DDOS attack. ‘Pulsing’ zombies semi-flood targeted websites with visitors. This type of attack slows down the website, but does not make its systems crash.

Because the degradation-type zombie does not crash the system, the targeted website may be affected for months or even years without anybody being aware.

On the last day of 2015, nearly all BBC websites suffered a cyber attack. A DDOS attacker sent instructions to his or her thousands of attack zombies, which targeted the websites.

Smartphone zombie attacks

Smartphone zombie attacks are more recent, believed to have begun in July 2009. Malicious software with **botnet capabilities have emerged for a rapidly-expanding smartphone market.

** A botnet is a number of devices – all connected to the Internet – that are used by a botnet owner to carry out various tasks, such as DDOS attacks.

July 2009 saw the ‘wild’ release of the Sexy Space text message worm, the first SMS worm to hit the smartphone market. The worm targeted Nokia smartphones’ Symbian operating system.

Also in July 2009, the Etisalat BlackBerry spyware program struck users in the United Arab Emirates.

Experts around the world disagree on the extent of the future smartphone zombie-virus threat. Some say we are at merely the tip of a giant iceberg, while others believe the outlook is significantly less dire.

Wikipedia quotes an interview with the New York Times, in which Michael Gregg, a cyber security expert, said:

“We are about at the point with [smart]phones that we were with desktops in the ’80s.”

Video – Zombie Computer!

In this The Next Genius video, the speaker explains how he became aware that his computer had been infected with a zombie virus.