What Are Common Types of Malware

What Are Common Types of Malware?

Diving into the most prevalent types of malware that can infect your system

Malware is a major risk to enterprises of all shapes and sizes. It takes on many forms to be harder to detect and protect against, increasing the danger it presents. By better understanding what types of malware exist, which are most common, and what their telltale signs are, enterprises can better defend their networks and keep them and their users safe.

7 Primary Types of Malware

There are countless types of malware out there, but some are more common than others. Here are the seven most common malware types and what they do:

1. Viruses infect devices and replicate by injecting their code into other programs. They can also spread to other devices, expanding the infection, but they require human assistance to spread. Viruses can cause serious damage to devices quickly.
2. Worms function much like viruses, but worms can spread on their own without the need for users to download an infected file or application.
3. Trojans, also called "Trojan Horses," give attackers access to devices, allowing them to steal sensitive information or remotely control your machine. These often masquerade as normal software programs but have malicious code within to gain access once you download and install them.
4. Ransomware encrypts files to block access unless a ransom is paid to unlock them. It often includes further threats to download/steal information and share or sell it for nefarious purposes. You should never pay the ransom for ransomware attacks, because there are no guarantees you will regain access to your files after paying.
5. Spyware, as the name implies, follows your activity on a device to steal information without your knowledge. This can include inputs in browsers such as credit card numbers or login details.
6. Adware is a malicious script that displays unwanted advertisements on your machine. Notoriously difficult to remove and often installed behind your back, Adware can use your bandwidth, slow down machines, and lead to data loss while occasionally installing other malware on a device.
7. Rootkits allow access to computers starting at a low level to avoid detection. Once installed, permissions escalate and eventually can lead to a full takeover of the machine. These often can be removed only by reformatting the hard drive.

Common Methods of Malware Installation

Several methods of installing malware exist, but three stand out above the rest: email attachments, phishing scams, and drive-by downloads.

We are all warned about infected email attachments. It is paramount to open attachments only from trusted sources that are expected: Unknown or unexpected files should be treated with extreme caution. Infecting attachments on emails is successful because users often open those attachments before checking for key risk signs.

Phishing scams, a key component of social engineering, create fake emails to trick users into taking an action. That action can include opening an attachment, clicking a link, or logging into a fake portal and handing over credentials willingly. Phishing has become more and more complex over the years but has some telltale signs that give it away. These include incorrect "from" addresses, rampant typos, an extreme sense of urgency (Do X immediately or Y will happen), and more.

Drive-by downloads can be triggered unknowingly when visiting an infected website. For example, a pop-up ad may have a close button that actually initiates the download of an infected file when clicked, infecting the device. There are ways to prevent these attacks, such as script blockers.

Detecting and Removing Malware

Breaches happen. That said, it is imperative to detect and remove threats quickly. Typically, the faster malware is removed from the system, the less damage it can cause.

There are several methods of detecting malware. For example, behavioral analysis is where you isolate software to identify which has malicious intent, observe it in a controlled environment, and determine where it is located to remove it. Dedicated solutions also exist to help detect and isolate malware, but, as with any solution, a combined effort of methods is ideal for providing adequate detection.

Declining device performance may also be an indicator of malware's presence. When malware is present, computers often run slowly, have reduced battery life, or struggle to perform basic functions.

Impacts of Malware

In addition to performance degradations, malware can have several impacts on devices and networks. First, it can cause data loss, because malware can steal, delete, or encrypt files that can be difficult or impossible to recover. Malware can also cause financial loss due to the time it takes to restore system functionality and potential penalties or settlements. Reputational harm is another negative impact of malware because customers can view brands that see major breaches as untrustworthy. Another risk is system damage, whether to the machine or network, caused by corrupted files, changed settings, or removal of system files, which can make the system unusable.

Malware attacks can have varying impacts and can lead to further attacks. Distributed denial-of-service (DDoS) attacks are one example of a secondary strike that follows a malware attack. They prey on security teams that are busy removing the malware to take down key websites, applications, and services.

How NETSCOUT Helps

NETSCOUT's network detection and response (NDR) solution helps detect abnormal network activity. NETSCOUT Omnis Cyber Intelligence (OCI) provides advanced NDR capabilities that can detect and isolate malware and other cyberthreats living in network environments. OCI also integrates with many extended detection and response (XDR) platforms to provide additional insights into the threats across your digital infrastructure.

Learn more about Omnis Cyber Intelligence.