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A botnet is a group of internet-connected devices, usually computers, infected with malicious software and remotely controlled by malicious players without the knowledge of the owners or authorized users. Using command-and-control (C&C) software, the bot herder can launch various attacks, including denial of service (DoS) and distributed denial of service (DDoS), to bring down corporate systems. Botnets can also be used to steal personal information, such as login credentials and credit card numbers.

What is a botnet?

A botnet is a network of infected computers remotely controlled by a malicious actor. The computers in a botnet can be used to launch attacks on other computers and networks or to perform other harmful activities. Attackers often use botnets to send spam emails, distribute malware, or carry out denial-of-service attacks.

In most cases, computers in a botnet are infected with malware that allows the attacker to take control of the machine and carry out malicious actions. Sometimes, the attackers even rent out their botnets to others.

Botnets can be very large, with some estimates suggesting the existence of millions of infected machines around the world. The largest known botnet was Storm, which reportedly had over one million infected machines at its peak. All botnets have one thing in common: they allow attackers to leverage the power of many computers to cause harm. 

How does a botnet work?

To infect users, hackers first scout for a flaw in a website, application, or user behaviour. The bot herder’s primary goal is to keep victims in the dark about their exposure to malware. Herders exploit the flaws in the system to spread malware via emails, drive-by downloads, or trojan horses and take control of the victim's devices. 

To turn computers into zombies, the herder uses various techniques, such as web downloads, exploit kits, popup advertisements, and email attachments. In centralized botnets, the C&C server routes infected devices to it. During peer propagation, the zombie devices try to connect to more infected devices if it’s a P2P botnet. Most threat actors prefer P2P botnet as it is an improvement over C&C botnet because law enforcement agencies cannot detect it.

After infecting enough machines, the bot herders launch their attacks. Zombies download the latest update from the C&C channel to receive their order. After executing its commands, the bot begins to engage in hostile behaviour. The bot herder can maintain and build their botnet remotely to carry out various operations. As the bot herder seeks to infect as many devices as possible to carry out malicious attacks, they seldom target specific individuals.

Who uses a botnet?

Cybercriminals use botnets to carry out various malicious activities: 

• Send spam emails

• Launch denial-of-service attacks

• Steal sensitive information

• Spread Malware

Botnets are often difficult to trace and can cause much damage, making them the weapon of choice among criminals. While a botnet is usually associated with threat actors, it has a positive value, too. Researchers can use it for high-speed distributed computing, biomedical research, climate modelling, and astrophysics, among other intensive tasks. 

What are the risks of having a botnet?

Botnets can infect thousands of computers and bring down even technological giants. Besides the financial damages, botnet attacks open organizations to various regulatory, reputational, and legal actions.

Another considerable risk is that a botnet can hijack your system and use it as part of a more extensive network to attack other organizations and steal information. Once someone wrests your system from your hands, it is next to impossible to regain control. 

How can you protect yourself from a botnet?

A botnet is an extensive network of infected individual computers woven together using malware. Often, small companies are ill-equipped to tackle such sophisticated attacks. However, taking precautions can reduce the probability of your systems or network coming under remote attacks.

Here are a few recommended steps: 

• Keep your software and operating system up to date with the latest security patches.

• Use a reputable antivirus program and scan your computer regularly for malware.

• Be cautious when opening email attachments or clicking on links from unknown sources.

• Do not download pirated software or visit illegal websites. These are often breeding grounds for malware.

Conclusion 

While it's challenging to detect whether a computer has turned into a zombie, security experts can help. They look for telltale signs of hijacking, like unexplained error messages, inexplicable lags, and denial of user access, among others, to diagnose issues. Security teams can effectively tackle botnets by using robust antivirus software, which covers a broad spectrum of devices on your network. For more details on securing your network against botnets, contact Packetlabs.