What is a botnet?

Overview

A botnet is a network of computers infected by malware and controlled by an attacking party. It may comprise millions of devices connected by the internet like mobile phones, IoT devices, PCs, and so on.

What are the components of a botnet?

There are two main components of a botnet:

• Bot: It is the device infected by the malicious code and becomes a part of the network of the other infected machines.
• Bot herder: It is an operator that leads the botnet with remote commands. Once the bots have been compiled, the herder uses command programming to carry out its activities. 

What are the motivations for botnet development? 

A botnet enables the attacking party to get resources and perform large-scale actions previously impossible with the malware. Some botnet commanders specialize in botnet development and expansion and sell their botnets to cyber criminals who carry out cyber attacks. Some of the common uses of botnet include:

• DDoS attacks 
• Data theft 
• Spam
• Phishing 
• Brute force attacks 
• Financial breach 
• Targeted intrusions 

How botnets are controlled

Attacking parties can control botnets using the following approaches:

Client-server botnet 

The client-server model involves a Command and Control (C&C) server. The attacker uses this server to operate the bots. It enables the attacker to control some or all of the bots simultaneously. 

Peer-to-peer (P2P) botnet

P2P relies on a decentralized approach. Each bot can act as a client and a server, making it very difficult to shut down.

What are the examples of a botnet?

Some of the well-known botnet attacks carried out in history include:

• Zeus 
• Game over Zeus 
• Methbott
• Mirai 

How to prevent botnet attacks

It is tough to detect a botnet attack as each attack is uniquely set up and operates differently. However, the following measures can be adopted to prevent your device from becoming a part of a botnet:

• Use strong device authentication.
• Update OS and install patches regularly.
• Secure remote firmware updates.
• Secure boot to ensure that the device only runs software by trusted parties.
• Use behavioral analysis to detect unusual behavior.
• Automate protective measures in IoT networks.