What is malware? Definition, types, and removal

What is malware?

The effects of malware infections can be anything from a mild annoyance to a full-blown security crisis. A minor adware infection might only flood your screen with pop-up ads, but ransomware can lock you out of your system, demanding that you pay thousands of dollars in ransom. In worst-case scenarios, malware attacks can lead to massive data breaches, exposing sensitive information and damaging reputations.  

The way malicious software operates depends on its type and purpose. Some malware, like viruses, latch onto legitimate files and need user interaction to spread. Others, such as worms, replicate themselves and spread across networks without user intervention. More advanced threats, like fileless malware, use built-in system tools to carry out malware attacks, making them even harder to detect.

One of the biggest dangers of malware is its ability to spread fast. Cybercriminals use malicious websites, infected email attachments, and compromised software to sneak malware onto devices without the user even knowing. A single click or download can put the entire system at risk, which is why strong network security measures are necessary for devices to stay protected.

What does malware do?

Malicious software can find its way onto devices through a variety of sneaky methods — email attachments, malicious websites, infected software downloads, and even malicious ads. Once inside, it can wreak havoc in various ways, which can include theft of sensitive information, financial fraud, espionage, and even the corruption of entire networks.

Some types of malware operate quietly in the background, gathering personal data like banking credentials and login details without the user ever realizing it. Others, like ransomware, strike immediately. They lock all files on the user’s device and demand a ransom payment for their release. These malware attacks may be catastrophic, especially for businesses, causing major financial loss and reputational damage. In extreme cases, entire networks may be compromised, leading to operational shutdowns and data breaches.

The longer malware goes undetected, the more damage it can do. A small infection might start with a minor slowdown, but if left unchecked, it can escalate into data theft, financial fraud, or a complete system lockdown. Being able to detect malware infections early can help prevent extensive damage. Here are some common signs of malware to watch for:

• Sluggish performance. If your device suddenly becomes slow or unresponsive or struggles with basic tasks, malware could be using system resources in the background.
• Frequent crashes or freezes. If your computer or phone keeps crashing, displaying error messages, or freezing unexpectedly, it may be infected.
• Unwanted pop-ups and browser redirects. If you're constantly bombarded with intrusive ads or find yourself redirected to shady websites, your system could be compromised by adware or other potentially harmful programs.
• Unusual network activity. Malware often communicates with external servers to send stolen data. If you notice excessive data usage or unauthorized connections, it’s a red flag.
• Suspicious logins or security breaches. If you receive alerts about logins from unfamiliar locations or notice changes to your online accounts that you didn’t make, malware could be harvesting your credentials.

Malware history

Malware has been around for decades. Its history dates back to the 1970s, when the first known malware program, Creeper, spread through ARPANET as a proof of concept. Back then, malware was more of a curiosity than a real threat.

By the late 1980s and early 1990s, viruses had already caused significant disruptions. In 1986, the Brain virus targeted floppy disks, marking the first PC-based malware example. As technology advanced, so did cyber threats. The 2000s brought a rise in botnets, worms, and trojans, which could steal data, control infected computers, and launch large-scale malware attacks.

Today, malware attacks are more sophisticated and far-reaching than ever. Cybercriminals use automation, artificial intelligence, and underground services like malware as a service (MaaS) to carry out malware attacks on a massive scale. No connected device is genuinely safe. Any device that plugs into a USB port — including lights, fans, speakers, and even toys — might be exploited to spread malicious code.

Types of malware and their examples

Malware comes in many shapes and forms, each with its own characteristics. Some types of malware are built to steal sensitive data, others to disrupt computer systems and take control of devices without permission. Below is a summary of different types of malware with examples.

For more details, check out our Threat Center or read more about all malware types and categories in our article.

Protection from malware

With rising malware statistics, securing your devices has never been more important. Staying one step ahead of cyber threats means knowing how to detect malware, remove it, and prevent it before it can cause real damage. Below are some steps to keep your devices safer and what to do if you suspect an infection.

How to get rid of malware

If your device is infected, your first priority should be to remove malware:

1. 1.Run a full system scan. Use a malware scanner to detect and remove threats. A deep scan with trusted antivirus or anti-malware software can help identify malicious files and quarantine them.
2. 2.Boot the device into safe mode and delete suspicious programs. Safe mode disables malicious programs from running during startup, making it easier to remove them.
3. 3.Uninstall suspicious applications. Follow your device's standard uninstallation process to remove malware or other unwanted software that might be harmful.
4. 4.Restore your system to a previous state. If you have a complete backup of your operating system and files or your device has a restore point set up, use it to roll back your system to a time before the infection occurred. Doing so will undo all changes made by the malicious software.

For more information, check out our complete guide to getting rid of malware.

How to prevent malware

Prevention is always better than a cure. To minimize the risk of malware, practice safe cybersecurity habits:

• Be cautious with emails and downloads. Avoid clicking unknown links or downloading suspicious attachments, especially if they come from someone you don’t know.
• Keep your software and devices updated. Regularly updating your operating system, browsers, and software will patch potential network security vulnerabilities.
• Practice safe browsing. Use a malicious website blocker or link checker before opening URLs from unknown sources to make sure they are not deceptive or harmful, and use VPNs with built-in protection features.
• Use strong passwords and multi-factor authentication. This way, you’ll improve the security of your accounts and prevent unauthorized access.
• Stick to reputable sources. Always choose trusted platforms and verify the legitimacy of what you're downloading.
• Install antivirus and anti-malware software. These tools will help catch cyber threats before they can cause serious harm.
• Use browser extensions. Ad blockers and anti-phishing tools will block harmful content and protect your online experience.
• Stay informed. Educate yourself about new malicious software and ways to protect yourself.

How to report malware attacks

While a direct "report malware" button doesn’t really exist, you can still take action by reporting cyber threats through the proper channels to help prevent further damage:

• If you become a victim of a malware attack, you can report the cybercrime to your country's cybersecurity organization or a law enforcement unit specializing in cybercrime. In the U.S., for example, the FBI’s Internet Crime Complaint Center (IC3) and the Federal Trade Commission (FTC) handle such reports.
• If you come across a site that appears to be spreading malware, you can report the website to search engines like Google and Microsoft Bing. Many browsers also have built-in features to flag and report dangerous sites.
• If you experience malware infections at work, immediately inform your IT security team so they can take action to contain and remove the threat.

Future trends in malware development

As technology gets smarter, so does malware, and the trends show it. Every day, over 450,000 new malware programs are detected.

One of the most alarming trends is the rapid rise in ransomware attacks. Back in 2011, only five major ransomware incidents were reported each year. Fast forward to 2024, and cybersecurity experts estimate that 20 to 25 major ransomware attacks take place every day.

Artificial intelligence (AI) is making malware smarter and harder to detect. AI-generated phishing attacks are becoming so convincing that 65% of phishing emails now bypass authentication checks, and 58% slip through traditional security filters. Cybersecurity experts attribute this trend to cybercriminals using generative AI to craft highly personalized and automated attacks, making phishing more dangerous than ever.

The latest concerning trend, however, is the use of Discord as a harmful software distribution platform. Malware programs discovered within the Discord app or distributed through Discord channels often disguise themselves as game cheats, software cracks, or other seemingly harmless files. Hackers are also using the platform to share phishing links and sell malware as a service, making it easier than ever for criminals to launch malware attacks.