The word ” botnet” is a combination of he words “robot” and “network”.A botnet is a number of internet -connected devices, each of which is running one or more than one bots.Botnets can be used to perform Distributed Denial-of-service attack (DDoS attack) and allow the attacker access to the device and its connection.We can control the botnet using command and control (C&C) software. Generally a botnet is a logical collection of internet connected devices such as computers, smartphones or IoT devices whose security has been breached and control to a third party.Computers in a botnet may also be infected with other types of malware,such as keyloggers that record our financial information and send it to a remote server.
A botnet can also be used to mine Bitcoins, which can then be sold for cash.It can also be used to send spam emails,sending emails dosen’t take much processing power, but it does require some processing power.And the spammers don’t have to pay for legitimate computing resources if they use a botnet.Generally some botnet may communicate in a distributed, peer-to-peer way.In this it may be possible to combat a peer-to-peer. Hundreds of thousands of computers would bombard a website with a traffic at a same time overloading it, and causing it to perform poorly, or become unreachable for people who actually need to use it.
The first botnets on the internet used a client-server model to accomplish their tasks.these botnets operate through Internet Relay Chat networks,domains, or websites.Each client retrieves the commands and executes them, clients send messages back to the IRC channel with the results of their actions.These bots may use digital signatures so that only someone with access to the private key can control the botnet.Many recent botnets now rely on existing peer-to-peer networks to communicate. These P2P bot programs perform the same actions as the client-server model, but they do not require a central server to communicate.
If our personal computer is part of a botnet, it’s infected with a type of malware. The bot contacts a remote server — or just gets into contact with other nearby bots — and waits for instructions from whoever is controlling the botnet. This allows an attacker to control a large number of computers for malicious purposes.Botnets could also be used for “click fraud” — loading websites in the background and clicking on advertising links to the website owner could make money from the fraudulent, fake clicks. A botnet could also be used to mine Bitcoins, which can then be sold for cash. Most of the computers can’t mine Bitcoin profitably because it will cost more in electricity than will be generated in Bitcoins,but the botnet owner doesn’t care.