A botnet is a network of internet-connected devices, such as computers, smartphones, or Internet of Things (IoT) devices, that have been infected by malware and 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. The owner of the botnet can control it using command and control (C&C) software. Botnets can be used to perform Distributed Denial-of-Service (DDoS) attacks, steal data, send spam, and allow the attacker to access the device and its connection. The scale of a botnet, which can be comprised of millions of bots, enables the attacker to perform large-scale actions that were previously impossible with malware. Botnets are created when the bot-herder sends the bot from their command and control servers to an unknowing recipient using file sharing, email, or social media application protocols or other bots as an intermediary. Once the recipient opens the malicious file on their computer, the bot reports back to command and control where the bot-herder can dictate commands to infected computers. Botnets are commonly used to send spam emails, engage in click fraud campaigns, generate malicious traffic for DDoS attacks, and distribute malware.