The internet is a marvelous invention, but just as any great thing in life, it can often be a double-edged sword. You have access to any kind of information in mere seconds, but your online activity can also leave you prone to malware attacks, which can steal your data and invade your privacy.

To put it simply, malware is a type of software that grants unauthorized individuals access to devices or networks with the purpose of sabotage, theft, or espionage. Viruses are one of the most common types of malware, but hackers have plenty of tools they can use to achieve their goals. 

Continue reading to find out more about the most common types of malware and how to detect them. 

Must Read: What Helps Prevent Cyber-Attacks?

Ransomware

Ransomware attacks use software that encrypts the target’s data, blocking access to it until a specific decryption key is provided. Some hackers block the entire system, while others only encrypt certain important files, but the result is always the same: the attacker will demand payment in order to provide a decryption key. 

One example is RobbinHood, a type of ransomware attack that hit Baltimore government’s computer systems. The attackers demanded 13 bitcoins to give back access to the systems, but the attack ended up costing the city over $18 million because it was forced to suspend activities such as tax collection, government email, and property transfers.

Adware

Adware is a less harmful type of malware in the sense that it does not install malicious software or code on a user’s device and does not log keystrokes. Still, what adware does is it tracks your online browsing activity to recommend ads that serve the attackers or their clients.

The biggest issue with adware is the invasion of privacy, as their online activity is monitored and valuable private information is captured. Although they are a must, strong passwords don’t work against malware, so consider installing a good antivirus to add an extra layer of protection. 

Trojans

Similar to the Trojan Horse that helped the Greeks win the war with Troy, a trojan virus is a code or software that is disguised to look desirable, but in fact, hides malware. Once downloaded, Trojan viruses can gain control over a system and make changes for malicious reasons. 

Trojans have been around for a very long time, but they were never as dangerous as they are today. They are usually hidden inside seemingly legitimate apps or programs, such as games, upgrade patches, or email attachments. Then, once the victim executes the file, the Trojan can start doing its work. 

Viruses

People often think that malware and viruses are one and the same, but vin fact, viruses are just a type of malware, and they are very different from Trojans or worms, for example. A virus is, in simple terms, a piece of code that infects an app or program and executes when the user runs that specific program. Once it penetrates a system, the virus can be used to steal data or launch cyberattacks. 

To differentiate viruses and trojans, you need to look at the method it executes and reproduces. Compared to a Trojan, which requires the user to only access the file once for it to execute and spread, viruses can only do their job when the app they infected is running, which is why it needs to spread very fast and reach as many apps as it can, in order to be effective. 

Worms

Worms are a type of malware that exploits network vulnerabilities and spreads through them. They can gain access through backdoors built in various files or, as you often see in movies, through flash drives. Once they enter the victim’s computer, they can be used to steal data and conduct ransomware attacks.

Worms don’t need the user to run a specific program or keep certain applications open, as they are self-replicating standalone software. One of the most notorious worms was the infamous ILOVEYOU worm, which made countless victims at the beginning of the 2000s. 

Rootkits

This is a type of malware that gives a hacker complete remote access to the victim’s computer. They can be integrated into apps, firmware, or kernels, and they often spread through malicious attachments and compromised files. 

Rootkits can often be used to conceal other types of malware, such as keyloggers, and have made many victims over the years. One example is Zacinlo, which is a type of rootkit that acts as an advertising click fraud. Once it gets into a person’s computer, the program checks and uninstalls any malware that may compete with it, then opens browsers that the victim does not see and starts interacting with them. The main purpose of this rootkit is to click on ads in these invisible browsers and hackers get a cut of the commission.