What are Bots, Botnets and Zombies?
A ’bot’, short for robot, is a type of software application or script that performs tasks on command like indexing a search engine, and they are really good at performing repetitive tasks.
Bad bots perform malicious tasks allowing an attacker to take complete control over an affected computer for the criminal to control remotely. Once infected, these machines may also be referred to as ’zombies’.
Taking over one computer is useful, but the real value to a criminal comes from collecting huge numbers of computers and networking these (a botnet) so they can all be controlled at once and perform large scale malicious acts.
zombie computer (zombie bot)
A zombie (also known as a bot) is a computer that a remote attacker has accessed and set up to forward transmissions (including spam and viruses) to other computers on the Internet. The purpose is usually either financial gain or malice. Attackers typically exploit multiple computers to create a botnet, also known as a zombie army.
Typically, a zombie is a home-based PC whose owner is unaware that the computer is being exploited by an external party. The increasing prevalence of high speed connections makes home computers appealing targets for attack. Inadequate security measures make access relatively easy for an attacker. For example, if an Internet port has been left open, a small Trojan horse program can be left there for future activation.
There are a few other kinds of zombies:
In one form of denial of service attack, a zombie is an insecure Web server on which malicious people have placed code that, when triggered at the same time as other zombie servers, will launch an overwhelming number of requests toward an attacked Web site, which will soon be unable to service legitimate requests from its users. A pulsing zombie is one that launches requests intermittently rather than all at once.
On the Web, a zombie is an abandoned and sadly out-of-date Web site that for some reason has been moved to another Web address. Such zombies contribute to linkrot.
In the UNIX operating system world, developers sometimes use the term to refer to a program process that has died but hasn’t yet given its process table entry back to the system.
The term originated in the West Indies, where a zombie is a will-less, automaton-like person who is said to have been revived from the dead and must now do the will of the living.