What is a Botnet?
A botnet is a network of devices infected with malware that comes under the control of a malicious actor. This device, called a “bot,” is then recruited to participate in various activities such as sending spam, stealing data, clicking on ads or conducting distributed denial-of-service (DDoS) attacks. The bots are connected to a command and control (C&C) infrastructure that enables the bot-herder to remotely manipulate them. The recruitment stage is often carried out through exploitation of vulnerabilities in software or hardware, leveraging social engineering techniques, exploiting weak authentication or cracking passwords to gain access. Some bots are designed to self-propagate by scanning for and infecting other devices such as printers, routers or security cameras.
Once a device is infected, the bot is ready to take action on commands from the C&C server. The bot can also receive updates to the malware from the C&C infrastructure which can change its functionality. Bots that use centralized resources like IRC networks, domains and web servers are more vulnerable to disruption as only a few points of failure need to be disrupted in order to bring the entire network offline.
Some bots are designed to target specific machines and gain backdoor access to high-value systems within an organization from which they can penetrate deeper into the corporate network. This can result in large-scale intrusions that could compromise critical data such as intellectual property, research and development, customer information or financial details. Other bots can launch DDoS attacks to flood servers with traffic, scout for unprotected devices to steal personal information and conduct other cybercriminal activities.