EXPLAIN What is a Botnet?

Cyber Security
#1

A bot is a piece of malware that infects a computer to carry out commands under the remote control of the attacker.

A botnet (short for “robot network”) is a network of computers infected by malware that are under the control of a single attacking party, known as the “bot-herder.” Each individual machine under the control of the bot-herder is known as a bot. From one central point, the attacking party can command every computer on its botnet to simultaneously carry out a coordinated criminal action. The scale of a botnet (many comprised of millions of bots) enable the attacker to perform large-scale actions that were previously impossible with malware. Since botnets remain under control of a remote attacker, infected machines can receive updates and change their behavior on the fly. As a result, bot-herders are often able to rent access to segments of their botnet on the black market for significant financial gain.

Common botnet actions include:

  • Email spam– though email is seen today as an older vector for attack, spam botnets are some of the largest in size. They are primarily used for sending out spam messages, often including malware, in towering numbers from each bot. The Cutwail botnet for example, can send up to 74 billion messages per day. They are also used to spread bots to recruit more computers to the botnet.
  • DDoS attacks– leverages the massive scale of the botnet to overload a target network or server with requests, rendering it inaccessible to its intended users. DDoS attacks target organizations for personal or political motives or to extort payment in exchange for ceasing the attack.
  • Financial breach– includes botnets specifically designed for the direct theft of funds from enterprises and credit card information. Financial botnets, like the ZeuS botnet, have been responsible for attacks involving millions of dollars stolen directly from multiple enterprises over very short periods of time.
  • Targeted intrusions– smaller botnets designed to compromise specific high-value systems of organizations from which attackers can penetrate and intrude further into the network. These intrusions are extremely dangerous to organizations as attackers specifically target their most valuable assets, including financial data, research and development, intellectual property, and customer information.