6 Types of Malware: How to Defend Against Them?

In today’s world where we have unlimited access to the internet, malware is one of the most common threats to cyber security. Malware or malicious software is any type of software that intentionally harms a computer, server, or network. These threats could either be a viruses, worms, ransomware, botnets, etc., and can harm any type of operating system or device like Windows, Android, and Mac. According to Statista, 6.06 billion malware attacks were discovered globally, most of them being in the Asia-Pacific region.

These malware are disguised as links or files that are harmless and can vary from impairing computer operations, and collecting sensitive data, to accessing private networks and displaying spam messages. Thus, it has become increasingly important for organizations to understand different types of malware, how they spread, and how they can detect and remove it.

This article is going to cover the types of malware in cyber security, what malware attacks are, common types of malware, and how to defend against them.

Understanding Malware

Malware is of various types but they have a common goal–to interfere or destroy an entity’s system infrastructure for financial gain. The transformation of the digital age has caused more and more cybercriminals to create sophisticated malware that could go undetected, infect the systems, and exfiltrate sensitive information.

Let’s look at how these malware evolved over the years–from a basic virus infecting a part of the system such as the CPU, to complex ones that can attack an entire organization’s infrastructure.

The Evolution of Malware

Malware has evolved a lot since the time it emerged. The history consists of five phases, starting from 1949 with basic malware such as worms and virus to the present time where it is specially created for unique purposes.

Early Phase of Malware: The early phase of malware began in 1949 with John Von Neumann stating the first virus as an idea of a “self-replicating string of code”. This malware wasn’t meant to harm the computer or steal sensitive data, instead, it was used to look for loopholes in MS-DOS systems. The malware caused a payload, making the system crash temporarily because of the consumption of system resources.

Additionally, this type of early malware wouldn’t stay hidden from the user. It could either show an image or a message on the user’s computer display. The early phase of malware lasted until 1991 before the emergence of the second phase which began in 1992.

Second Phase of Malware: The Windows Operating System attracted a lot of users due to how simple it was to use and its powerful user interface. However, simultaneously, it also attracted hackers and attackers. Hence, most of the malware such as early mail worms, and macro worms were targeted to attack the Windows Operating systems. This phase lasted until 1999 before the third phase of malware began.

Third Phase of Malware: The third phase of malware began in 2000 when the internet was at its highest peak. This phase saw an increasing amount of network worms and viruses transmitted easily either through email, downloads from websites that were compromised, or open network shares.

Fourth Phase of Malware: The fourth phase of malware evolution started in 2005 when the public was introduced to Ransomware and Rootkits.  This phase of malware had become much more prevalent as attackers would use several methods to infect the user’s computer such as:

• Sending phishing emails
• Sending email attachments with free downloads from hacked websites
• Through USB
• Through other removable media

In this phase, the malware’s intention was mostly for financial gain or illegal control of the machines it had infected. This phase lasted until 2016 before the evolution of the fifth phase of malware, the current phase.

Fifth Phase of Malware: The fifth phase of malware started way back in 2010. This malware was specifically architectured for virtual espionage and to sabotage the work of either an individual or an entire organization. While previous malware was created by cyber criminals who would target users or businesses, the current malware is far more powerful as they are created by not just the non-state forces, but by the state actors of various countries.

This phase of malware evolution has the potential to severely damage human lives. It’s labeled as ‘Advanced Persistent Threat’ or APT, meaning that APT is not just a simple malware, but one that’s planned with a specific target in mind.

In the early phases, malware could easily be detected and was harmless, perhaps causing little to no frustration from the user’s side, but as it evolved, the malware’s intentions too became more sophisticated over time. From ransomware to espionage, individuals and companies get threatened by cybercriminals for financial and other gains.

However, while cyber attackers are developing novel ways to harm an organization’s system infrastructure, companies and businesses too are spending billions of dollars to strengthen their cyber security so that they can counter any and all possible threats.

What are Malware Attacks?

Malware attacks are one of the most common types of cyberattack where malicious software performs unauthorized actions on a user’s system. This type of software can be of different types such as ransomware, spyware, virus, or a worm. More often than not, a cybercriminal creates malware with a certain objective in mind. It could range from:

1. Stealing data: Most malware focuses on stealing important data such as a user’s personal information, medical records, payment information, credentials, Social Security numbers, etc. This type of malware can be expensive for individuals and organizations alike.
2. Disrupting computer operations: Some malware are specially created to interfere with networks or systems. The disruptions could vary; from corrupting files in the operating system to attacks on large-scale distributed denial of service (DDOS).
3. Extorting money: Cyberattackers and criminals use ransomware to encrypt an organization’s or a user’s data or hold the computer’s systems hostage, thereby demanding payment, often in cryptocurrency for anonymity.
4. Gaining remote control: Some malware are able to provide cybercriminals control over the user’s system, enabling them to remotely use it for malicious purposes such as deleting or modifying files, or implementing additional malware attacks.

Why Do Cybercriminals Use Malware?

The end goal for cybercriminals to use malware is either for financial gain, espionage, or to cause disruption. They extract important data such as passwords, emails, financial data, and even healthcare records from the user’s computer systems and use it as leverage over the victims. Attackers sell the data they collected on the dark web or use it to carry out fraudulent payments.

These cybercriminals trick users by means of social engineering into performing certain actions so that they can get unauthorized access to their networks. Moreover, organizations who hold critical information are more likely to be targeted by these attackers as those data can be particularly lucrative.

Malware has become one of the most powerful tools for cybercriminals; especially attacking those who have weak cybersecurity or lack the knowledge thereof. While many just want to cause chaos or infect a computer for fun, there are some who are highly motivated and aim to sabotage businesses and individuals alike.

6 Types of Malware

There are many types of malware in cyber security, and it’s important that every individual and organization should be aware of them so that they can implement strategies to evade these cyber threats. Below are the 6 types of malware and details on how they work.

1. Virus

A virus malware modifies other computer programs and inserts its own code to self-replicate. Once activated at a specific time or under a specific condition, it can perform a number of tasks that it was programmed to do such as encrypting important data, deleting files, disrupting security settings, or taking control of the entire system.

This malware exploits weaknesses in the system to infect and spread the virus–frequently targeting operating systems such as Windows and Mac. However, viruses can also infect IoT devices and Linux machines as well. When a computer is infected by the virus, it begins to display certain symptoms such as:

• Frequent freezing or crashing
• Applications or programs may lag or perform slowly
• Frequent pop-up ads that are disguised as legitimate websites
• Unknown changes to passwords
• Unfamiliar programs starting up after turning on the computer
• Difficulty in restarting or shutting down the computer

Hence, it’s always a good habit to occasionally run a computer virus scan to ensure that no virus has exploited your system.

Developed in 1982, the first computer virus was Elk Cloner. It was created as a prank by Richard Skrenta who was just fifteen years of age. Skrenta created the virus for Apple II operating system where it would jump from one floppy disk to another on computers that had multiple floppy drives. As a result, whenever an infected computer booted up every 50th time, a poem written by Skrenta would show on the screen.

Elk Cloner was just created as a joke simply to frustrate the users and not to cause any damage to the systems.

The most popular way to defend against viruses is to install antivirus software. Additionally, it’s important to keep all computer systems updated and patched and ensure timely vulnerability assessments.

2. Worm

A computer worm is not that different from a virus; it self-replicates and its objective is to infect other computers by staying active on systems that are infected. They are spread through the targeted computer’s networks such as the internet, emails, file-sharing platforms, and torrents, and rely on vulnerabilities and security failures to gain access to it.

However, unlike viruses, worms don’t need the user to take any action. It can simply sit back and exploit other files and programs to do the harm. It can move around the system’s environment and create copies of itself by its own will.

One of the first widespread computer worms is the Morris Worm, created in 1988 by Robert Morris, a Cornell grad student. He had created the Morris Worm to demonstrate the widespread security flaws, however, things took a turn when the worm spread like wildfire after its release, targeting multiple computer weaknesses and infecting 10% of all computers connected to the internet – within 24 hours.

While this worm wasn’t created with the intent of causing harm, it became the first malware to cause significant financial damage, costing businesses millions of dollars.

To defend against a computer worm, the first and foremost thing is to update the software and passwords regularly and to avoid clicking on pop-up ads or downloading files from unknown sources. It’s also important to be cautious when opening email attachments or links associated with the email.

3. Trojan Horse

True to its name, the trojan horse malware disguises itself as a legitimate program, hiding its true intention to cause harm to the computer system. Trojans can easily be spread by phishing where a user may click an email attachment with a legitimate file such as an Excel sheet or a PDF.

Trojans have been a popular weapon amongst cybercriminals as it acts as a backdoor to control other computers.  In fact, most trojans come in the form of antivirus pop-up ads, persuading users to “install” the antivirus on their computer. Once the file is opened, downloaded, or installed, the trojan takes its effect by allowing attackers to have remote access of the computer’s systems. It can delete or steal important data, spy on the victims, and even launch DDoS attacks.

One such example of a trojan horse is CryptoLocker. Cyberattackers use social engineering to trick users by disguising CryptoLocker attachments as unsuspecting emails from real businesses such as FedEx or UPS tracking notices to click on the email attachments. Once the infection has taken place, users need to pay a ransom to recover or decrypt their files.

To defend against trojan horses, there are several effective methods organizations can implement such as:

• Installing legit antivirus software
• Updating software regularly
• Avoiding downloading files or links from unfamiliar sources
• Using strong passwords
• Enabling multi-factor authentication

By implementing these multi-layered security strategies, users can prevent cyber attackers from gaining unauthorized access to devices and systems.

4. Rootkits

To simply put, rootkits give cybercriminals control of a computer without the user’s consent. The meaning of root in the rootkit defines the “root user” or “admin” while kit means a package of software tools. This type of malware is dangerous as they give root-level access and are created in a way that would hide its own presence in a gadget.

Rootkits can get into the system through phishing email thereby allowing cybercriminals to remotely control a machine. Rootkits are used for various purposes such as:

• Disabling antivirus software
• Spying on a user’s activity
• Stealing important information
• Executing other types of malware

Rootkit spread by the same way a virus or a worm would spread–by downloading corrupt files from untrusty sources and spam emails. Unlike other malware that show symptoms, rootkits are stealthy. They can bypass a system’s security software enabling cyberattackers to get backdoor access.

One real-world example of rootkit malware took place in 2005 with Sony BMG, one of the famous music companies. As stated by the Electronic Frontier Foundation (EFF), the company embedded a rootkit in their CDs – approximately 22 million – with the intention of preventing piracy.

When a user would play one of the CDs on their device, the rootkit would stealthily install by itself and hide deep inside the system. This rootkit opened doors to many security flaws and exposed millions of users to cyber threats.

To protect devices from malware like rootkits, it’s crucial for organizations and individuals to scan their systems frequently, avoid clicking on suspicious links or emails that may oftentimes appear legitimate, update software, and install anti-malware software from a trusted source.

5. Ransomware

Ransomware prevents the user from accessing their computer or specific data until an amount demanded for ransom is paid. Ransomware can easily be spread by visiting websites that are infected, phishing emails, or through system vulnerabilities. A few symptoms of ransomware would include leakage of data, system downtime, breach of data, and intellectual property theft.

One of the most well-known ransomware is WannaCry. In 2017, WannaCry spread across some important systems and exploited a flaw in Windows known as EternalBlue, thereby encrypting the files stored in the PC’s hard drive. This made it impossible for users to access their own files, however, with a ransom in the form of Bitcoin, they were able to decrypt and access their files.

To defend against ransomware, there are a number of steps organizations can take as a security measure:

1. Keep operating systems updated and patched
2. Avoid installing software from untrusted sources
3. Avoid giving administrative privileges to certain users
4. Regularly back up files

These defensive steps can help prevent a ransomware attack and improve a system’s defenses from other types of cyber threats.

 6. Keylogger

Keyloggers are a stealthy type of malware where cyberattackers monitor and record what a user types on their keyboards. A keylogger attack is when every keystroke is recorded and sent to the cybercriminal. Since almost all of the information in devices is typed in, it’s easier for cybercriminals to track sensitive data such as credit card information, emails, and passwords of bank accounts, and steal information by gaining access to a company’s network.

Most of the time keyloggers are used for legal purposes such as tracking an employee’s work hours, troubleshoot issues on devices or even parents monitoring their child’s time on the device. However, those with malicious intent use keyloggers to execute cybercrimes. Keyloggers allow attackers to know what the victim types, which websites they visit, and understand more about them.

Ghost Keylogger is one such keylogger that originated in the 2000s. It’s a software-based keylogger that could be installed on a user’s device physically or through malware distribution. It was software that could see what a user did, recording their keystrokes, storing it in a file and sending the file to the cyber attackers. This malware compromised a user’s secured and private information such as sensitive information such as passwords, usernames, and financial data. The attackers used the stolen data to commit identity fraud or gain access to restricted accounts.

Just like any other malware, following the below steps would ensure that the system can defend itself against keyloggers.

1. Install antivirus and anti-malware from trusted sources.
2. Frequently update software and applications to patch system vulnerabilities.
3. Avoid clicking on links or opening email attachments that may appear suspicious.
4. Use virtual keyboards to enter sensitive data like usernames and passwords.
5. Regularly perform scans to detect malware and viruses.

How to Detect and Remove Malware?

When a computer is infected with a virus or malware, it will start to act abnormally. A user may find unknown or suspicious files and applications downloaded in their system too, or the computer would show unwanted pop-ups, freeze, or crash frequently. The system may not even allow you to install new software or remove old ones.

In many PCs, there’s a chance of overheating and loud noise from the fans. Additionally, computers that have hard drives may hear a whirring sound. All of these signs indicate that there’s something wrong with the computer, or that the system has been breached.

Once malware has been detected, it’s important to quickly implement strategies to remove it and to further prevent it from spreading through the entire system.

1. Avoid using the system: Since most of the sensitive information that a user inputs is through the internet for purposes like shopping, online banking, etc, it’s important to stop those for a while until there’s a surety that the computer is free of any malware.
2. Install antivirus and anti-malware software: If a system lacks software that automatically scans viruses and malware, malware can easily get inside the system and infect it. More often than not, these malware are allowed by downloading files from unfamiliar sources or clicking on infected websites.
3. Regular updates: It’s important to regularly update newly installed or previously installed security software as these updates can prevent malware from infecting the systems.
4. Frequent device scans:  If the system acts abnormally, then running a scan without waiting for the software to do it on its time can be crucial in preventing a malware from entering the system. It’s also important to observe files that are unfamiliar and delete them.
5. Reinstall Operating System: Oftentimes, it’s doubtful whether a malware has been prevented or not. However, if the computer continues to face issues like lagging, crashing, overheating, and similar symptoms, it’s a good idea to reinstall the operating system. Before reinstalling the operating system, it’s important to back up all important data as reinstalling the system would mean loss of stored data.

Malware Detection and Mitigation with SentinelOne

SentinelOne is an industry-leading enterprise security platform that protects against malware and cyber threats. Singularity™ Endpoint provides autonomous protection for endpoints, servers, mobile devices, and attack surfaces. It can conduct machine-speed malware analysis and combat ransomware, spyware, and fileless attacks.

Singularity™ Cloud Security is the ultimate CNAPP solution for fighting malware across on-premises, cloud, and hybrid environments. It features a unique Offensive Security Engine™ and is powered by a mix of patented Storylines™ technology and Verified Exploit Paths™. It offers runtime protection designed for production environments with mission-critical durability. It is also built on the eBPF architecture and is the world’s most trusted and awarded cloud security suite.

Singularity™ Cloud Security’s core capabilities are Kubernetes Security Posture Management (KSPM), Cloud Security Posture Management (CSPM), Infrastructure as Code Scanning (IaC), Secret Scanning, AI-SPM, Vulnerability Management, External Attack & Surface Management, Cloud Detection & Response (CDR), Cloud Workload Protection Platform (CWPP),  and Cloud Infrastructure Entitlement Management (CIEM).

To learn more about SentinelOne’s offerings, book a free live demo. We can help you defend against different types of malware attacks.

Conclusion

While the internet is a safe space, there’s no doubt that there are cybercriminals hiding behind at every corner, ready to attack. They are ever-ready to cause chaos and one such method they use is by spreading malware and harming a system’s infrastructure for profit. These malware come in various forms; either as a virus, a worm, rootkits, or ransomware. Organizations should be aware of these cyber threats as they pose a significant risk to the entire system and all those connected in the shared network. By implementing cyber security strategies, businesses not only prevent malware from infecting their system environment but also avoid reputational damage and potential financial loss.

FAQs

1. Is malware a virus?

A malware is not the same as a virus. Malware, also known as malicious software is an umbrella term for any software that’s malicious; specially made to harm and infect a system.  malware could be of various types including worms, trojan horses, spyware, etc. Whereas a virus is one type of malware that self-replicates and spreads across other devices.

2. What is malware classification?

Malware classification means assigning a type of malware to a specific category. Malware within a certain category shares the same characteristics such as code behaviors, patterns, and impact. Classifying these malware can help cyber security teams to distinguish the unique types of malware, and understand how it works, what its outcome would be, and how best to detect and prevent it.

3. How does malware typically spread?

Malware can be spread by different means such as:

1. Downloading or installing software from unfamiliar sources.
2. Opening or clicking on email attachments and suspicious links.
3. Visiting infected websites.
4. Connecting to infected devices such as USB flash drives.

Once the malware gets into the system, it does not take much time for it to spread throughout the infrastructure. If an organization is using a shared network, then it puts other individuals and businesses at risk too.

4. What are the best ways to protect my system from malware?

The best way to protect a system from malware is to:

1. Always keep your computer and software updated. These updates improve the overall security of the operating system and may also employ automatic security updates as soon as they’re ready.
2. For mundane matters such as web browsing, playing games, or signing up on websites, it’s ideal to use a non-administrator account as this will prevent any malware installations.
3. Limit file sharing as some websites have little to no protection against malware.
4. Install anti-malware software from a trusted source and regularly scan the system to catch malware before they are spread.