What is a Botnet?
A botnet is a network of devices, such as computers (PCs and servers), mobile phones, and Internet of Things (IoT) devices that are infected with malware. The infected devices are controlled remotely by threat actors, often cybercriminals, to perform automated attacks that stay hidden from the end-user. Botnets are commonly used for cryptocurrency mining, ad fraud campaigns, distributed denial-of-service (DDoS) attacks and the distribution of ransomware.
In order to receive instructions from a bot-herder, infected devices must communicate with a command and control (C&C) server. This communication can be centralized through a client-server model or decentralized through a peer-to-peer (P2P) approach. In order to evade detection, these communications are typically encrypted.
Once infected, bots monitor for commands from a C&C server through data posted on websites or social media channels, and responses to DNS queries. The bots will then execute the commands. Bots may also deliver information back to the C&C server as well.
In addition to being an effective tool for malicious activity, botnets are also valuable assets to threat actors that can be rented or sold to others (botnet-as-a-service). The most common use cases include cryptocurrency mining, phishing, password attacks and ransomware. Ensure that devices in your network are not being recruited for botnets by implementing strong passwords and regular software updates. Additionally, ensure that IoT devices are protected with a firewall and other security measures to minimize vulnerabilities. This can help prevent devices from becoming part of a botnet and avoid issues like higher Internet costs, compromised data and legal consequences.