What is a Botnet?

The term "botnet" is a combination of "robot" and "network" and refers to a network of infected machines that can be controlled remotely. A botnet can include millions of devices scattered across various locations. Computers, cellphones, and other Internet-connected devices can be infected and become part of a botnet without the user's knowledge, including yours!

Botnet malware is designed to be difficult to detect, remaining active in the background and only activating when receiving commands from the botnet controller.

Once activated, these machines can be used for various purposes, such as sending spam, obtaining the user's personal data, and launching attacks like Distributed Denial of Service (DDoS) attacks, where many machines target the same system to overload it. They can even be used for cryptocurrency mining on the host machine.

Malware can infect devices in different ways. Users might be tricked into clicking on malicious links in emails or on websites, or their devices might be infected through media such as USB drives or other compromised devices on the network. Attackers might also directly install malware on a device by exploiting outdated systems or weak passwords.

To prevent your machine from being infected by malware, including botnets, consider the following:

1. Don’t open suspicious files or links;
2. Keep your operating system and programs up-to-date;
3. Change the default access credentials (login and password) on your devices;
4. Use a firewall;
5. Create strong passwords;
6. Use antivirus software on your computer, keep it up-to-date, and perform regular scans;
7. Install and download only original apps and software from trusted sources. In the case of smartphones, only download apps from the official store or from the device manufacturer.

Despite being difficult to detect, there are some signs that may indicate a malware infection, such as slow Internet speeds, unexpected error messages, and unusual Internet consumption and processing activity. If you suspect that your device is infected, try using a specialized malware removal tool.

However, in many cases, formatting the device may be necessary, so make sure you update your backups regularly.

More information: https://cartilha.cert.br/fasciculos/#codigos-maliciosos (Portuguese only)

Video Description

In the first scene, a character representing an attacker sends malware to a group of computers each displaying a happy face on their screen. As the computers are infected, one by one the happy faces turn into zombies. The phrase "Ever heard of botnets?" appears above, followed by the first part of another sentence: "It's a network of infected devices..."

In the next scene, more infected computers and cellphones appear. The sentence continues with "that act like zombies controlled by an attacker" and "sending spam, viruses, or launching DDoS attacks."

Another computer appears, and the attacker indicates that the infected machines will attack the new computer. The machines then begin sending emails, malware, and launching attacks against the computer. Small explosions suggest that the attack has been successful until the computer displays an error message in the form of a white exclamation mark inside a red circle.

The final phrase appears at the top of the screen: "Protect yourself!"