Botnets are networks of infiltrated devices used by hackers to launch cyberattacks on one another, so using an antivirus tool with advanced detection features is essential to identify and eliminate botnet malware early on.
Hackers gain control of devices in a botnet by using remote access tools (RATs). This enables them to attack other systems remotely.
What is a Botnet?
Botnets are networks of infected devices linked to the internet that are controlled by cyber attackers, infiltrating thousands or millions of computers (known as zombie bots ). Once hackers gain control over such networks they can employ it for numerous malicious attacks on numerous fronts.
Computers infected with botnet malware are remotely managed by the hacker responsible, known as the bot herder. As soon as an infected machine becomes part of a botnet, it establishes communication channels with this server through covert channels to contact its master (bot herder).
Early botnets used web pages or domains as command and control servers, making their locations obscure and making them hard to take down. More modern botnets operate via P2P technology, where each bot contacts other bots for instructions from the C&C server; their herder still controls each individual bot, but this architecture makes taking down an entire botnet more difficult; in turn this architecture also enables attacks such as DDoS attacks and spamming campaigns to continue with less chance of failure. Botnets are increasingly used for automated attacks including DDoS attacks and spamming campaigns against targets of interest.
How Does a Botnet Work?
Hackers install malware onto internet-connected devices (PCs, smartphones, smart home appliances and network routers) which monitor for instructions from the botnet’s command-and-control (C2) server and execute them when received.
These attacks could include stealing personal information and login credentials, disrupting services or attacking websites and apps. The more bots a network contains, the stronger its attack.
Cybercriminals often create and utilize botnets for different reasons; most commonly they seek to gain entry to something, disrupt services, or simply generate profit.
Moneymakers may rent or sell access to their botnet, while others use botnets for other attacks, including phishing, scamming, password hacking or DDoS attacks.
Famous Botnet Attacks
Botnets – networks of compromised computers used by hackers to do their bidding without their owners’ knowledge – have long been a menace, from Agobot, one of the first ever botnets, to Zeus which stole millions from investors; their creators remain unknown and these harmful networks continue to cause havoc today.
These networks may engage in illegal activities ranging from sending spam emails and distributing malware, to launching DDoS attacks. Most often their illicit activities go undetected by victims except when there are noticeable changes in system files or programs.
Botnets have become an increasingly popular form of attack through malware infections or phishing attacks, typically with the aim of gathering data, accessing personal information or exploiting security gaps in web browsers and software applications. Most botnets utilize central control-and-command servers for communication with infected machines; however, recently hackers have begun employing peer-to-peer deployment methods, which allows infected machines to scan for other bots on the network and share updated commands between themselves.
Types of Botnet Attacks
Attackers utilizing bot attacks typically seek to infect multiple devices (commonly referred to as zombie bots) with malware and use these remote control machines without their owners being aware of what’s going on.
Once an attack commences, attackers can use compromised devices to conduct any number of activities – from mining cryptocurrency and sending spam emails, to flooding servers with traffic in an attempt to disrupt service, and DDoS attacks. The more zombie bots a threat actor controls, the larger and more sophisticated their attack becomes.
Bots can evade detection by running on devices’ default settings and employing standard communication methods, such as Internet Relay Chat (IRC) channels or web-based protocols such as HTTP. This makes blocking their activity or even detecting it difficult for security systems; that is why a robust security solution is so vital – one which monitors each device for signs of suspicious or unknown activity while terminating communications between centralized command-and-control servers and these threats.
1. Phishing
An attacker behind a botnet employs various tactics to compromise your device, from social engineering you into making an inappropriate drive-by download or exploiting vulnerabilities in browsers or programs to exploiting vulnerabilities themselves – whatever method they employ to gain entry, cybercriminals will then co-opt it into their network and co-opt your device into it as part of it.
Once an attack begins, infected computers – known as zombie bots – will communicate back with the hacker through secret channels, reporting back for instructions on which actions the infected computers should perform. A hacker, also referred to as a bot herder, can then direct this infected computer’s actions by manipulating covert channels.
Bots can perform many useful tasks, from stealing passwords and recording keystrokes, to ejecting people from chatrooms and recording keystrokes – but when used maliciously they can have devastating results.
Any computer, laptop or other device connected to the internet can become a target of botnet recruitment. One way of checking if this occurs on your device is by looking for programs consuming large amounts of disk resources – an easy way of doing this can be found by opening Task Manager and sorting your programs according to disk usage.
2. Distributed Denial-of-Service attack
Distributed denial-of-service attacks (DDoS) are one of the most frequent forms of botnet attack, comprised of thousands or even millions of malware-infected devices that attackers remotely control to launch cyber attacks on networks. This swarm can flood infrastructure with traffic that cripples your service, steal data or deliver ransomware; or it could cause physical damage like Saudi Aramco’s Stuxnet malware altered industrial control processes in order to destroy centrifuges.
Hackers recruit hardware devices into their botnet army through various means such as exploiting web vulnerabilities, exploit kits and popup ads. Once recruited, hackers use bot malware to infuse each device with zombie programming so they can be controlled by a bot herder.
These zombie bots are then told to communicate and launch a DDoS attack against the target infrastructure, like 2016’s Mirai DDoS attack, which recruited hundreds of thousands of Internet of Things devices into its army and caused performance disruptions and even outages of major services like Twitter and SoundCloud. While some botnets use central command-and-control servers, others such as Slowloris and SlowDroid botnets communicate peer-to-peer; thus making them less susceptible to disruption due to single points of failure.
3. Spambots
Cybercriminals utilize bots to send spam emails, generate malicious traffic for distributed denial-of-service attacks (DDoS), perform click fraud on ads and infect devices with malware – including personal computers, servers, mobile phones and internet of things (IoT) devices. Most people don’t realize their devices have been infiltrated – although three major places where people encounter spambots include websites, social media and email.
Spambots exist with one goal in mind: spreading spam. They accomplish this task by searching websites without user accounts to post comments containing preprogrammed responses or creating fake accounts on platforms and sharing backlinks for better search engine rankings.
Credential stuffing bots are widely known, with these automated attacks targeting login and account pages to harvest credentials and other forms of sensitive data from them. Cybercriminals use stolen credentials to gain entry to accounts or conduct fraudulent activity with substantial profits for themselves resulting from these stolen credentials.
How to Protect Against Botnets?
Maintaining security against bots requires taking several measures. First and foremost, always utilize a reliable antivirus program as this will prevent most forms of bot malware from ever reaching your device in the first place. Also make sure that updates and patches are installed as soon as available.
Avoid downloading files from unknown email senders unless you can verify who and what the file is before opening it. Don’t click any links within messages and don’t install programs you weren’t expecting or which have come through unsecure networks.
Make sure all internet-connected devices on your network have adequate security settings – this applies to everything from domestic appliances and DVRs to smartwatches and IoT surveillance cameras. Consider running ingress/egress filtering to detect malicious data packets before they enter/exit your network; this will stop botnets from communicating with their central command server and thus disabling their attacks.