'Just tell me how to fix my computer:' a crash course on malware detection

‘Just tell me how to fix my computer:’ a crash course on malware detection

Malware. You’ve heard the term before, and you know it’s bad for your computer—like a computer virus. Which begs the question: Do the terms “malware” and “computer virus” mean the same thing? How do you know if your computer is infected with malware? Is “malware detection” just a fancy phrase for antivirus? For that matter, are anti-malware and antivirus programs the same? And let’s not forget about Apple and Android users, who are probably wondering if they need cybersecurity software at all.

This is the point where your head explodes.

All you want to do is get your work done, Zoom your friends/family, Instacart a bottle of wine, and stream a movie till you go to bed. But it’s during these everyday tasks that we let our guard down and are most susceptible to malware, which includes such cyberthreats as ransomware, Trojans, spyware, stalkerware, and, yes, viruses.

To add insult to injury, cybercriminals deliver malware using sneaky social engineering tricks, such as fooling people into opening email attachments that infect their computers or asking them to update their personal ~~~information on malicious websites pretending to be legitimate. Sounds awful, right? It sure is!

The good news is that staying safe online is actually fairly easy. All it takes is a little common sense, a basic understanding of how threats work, and a security program that can detect and protect against malware. Think of it like street smarts but for the Internet. With these three elements, you can safely avoid the majority of the dangers online today.

So, for the Luddites and the technologically challenged among our readership, this is your crash course on malware detection. In this article, we’ll answer all the questions you wish you didn’t have to ask like:

  • What is malware?
  • How can I detect malware?
  • Is Windows Defender good enough?
  • Do Mac and mobile devices need anti-malware?
  • How do you remove malware?
  • How do you prevent malware infections?

What is malware?

Malware, or “malicious software,” is a catchall term that refers to any malicious program that is harmful to your devices. Targets for malware can include your laptop, tablet, mobile phone, and WiFi router. Even household items like smart TVs, smart fridges, and newer cars with lots of onboard technology can be vulnerable. Put it this way: If it connects to the Internet, there’s a chance it could be infected with malware.

There are many types of malware, but here’s a gloss on the more infamous and/or popular examples in rotation today.


Adware, or advertising-supported software, is software that displays unwanted advertising on your computer or mobile device. As stated in the Malwarebytes Labs 2020 State of Malware Report, adware is the most common threat to Windows, Mac, and Android devices today.

While it may not be considered as dangerous as some other forms of malware, such as ransomware, adware has become increasingly aggressive and malicious over the last couple years, redirecting users from their online searches to advertising-supported results, adding unnecessary toolbars to browsers, peppering screens with hard-to-close pop-up ads, and making it difficult for users to uninstall.

Computer virus

A computer virus is a form of malware that attaches to another program (such as a document), which can then replicate and spread on its own after an initial execution on a system involving human interaction. But computer viruses aren’t as prevalent as they once were. Cybercriminals today tend to focus their efforts on more lucrative threats like ransomware.


A Trojan is a program that hides its true intentions, often appearing legitimate but actually conducting malicious business. There are many families of malware that can be considered Trojans, from information-stealers to banking Trojans that siphon off account credentials and money.

Once active on a system, a Trojan can quietly steal your personal info, spam other potential victims from your account, or even load other forms of malware. One of the more effective Trojans on the market today is called Emotet, which has evolved from a basic info-stealer to a tool for spreading other forms of malware to other systems—especially within business networks.


Ransomware is a type of malware that locks you out of your device and/or encrypts your files, then forces you to pay a ransom to get them back. Many high-profile attacks against businesses, schools, and local government agencies over the last four years have included ransomware of some kind. Some of the more notorious recent strains of ransomware include Ryuk, Sodinokibi, and WastedLocker.

How can I detect malware?

There are a few ways to spot malware on your device. It may be running slower than usual. You may have loads of ads bombarding your screen. Your files may be frozen or your battery life may drain faster than usual. Or there may be no sign of infection at all.

That’s why good malware detection starts with a good anti-malware program. For our purposes, “good” anti-malware is going to be a program that can detect and protect against any of the threats we’ve covered above and then some, including what’s known as zero-day or zero-hour exploits. These are new threats developed by cybercriminals to exploit vulnerabilities, or weaknesses in code, that have not yet been detected or fixed by the company that created them. (That’s why when companies do fix these vulnerabilities, they issue patches, or updates, and notify users immediately.)

Antivirus and other legacy cybersecurity software rely on something called signature-based detection in order to stop threats. Signature-based detection works by comparing every file on your computer against a list of known malware. Each threat carries a signature that functions much like a set of fingerprints. If your security program finds code on your computer that matches the signature of a known threat, it’ll isolate and remove the malicious program.

While signature-based detection can be effective for protecting against known threats, it is time-consuming and resource-intensive for your computer. To continue our fingerprint analogy, signature-based detection can only spot threats with an established rap sheet. Brand-new malware, zero-day, and zero-hour exploits are free to spread and cause damage until security researchers identify the threat and reverse-engineer it, adding its signature to an increasingly bloated database.

This is where heuristic analysis comes in. Heuristic analysis relies on investigating a program’s behavior to determine whether a bit of computer code is malicious or not. In other words, if a program is acting like malware, it probably is malware. After demonstrating suspicious behavior, files are quarantined and can be manually or automatically removed—without having to add signatures to the database.

The best anti-malware programs, then, can protect against new and emerging zero-day/zero-hour threats using heuristic analysis, as well as threats we already know about using traditional signature-based detection. If your antivirus or anti-malware relies on signature-based malware detection alone to keep your system safe—you’re not really safe.

Is Windows Defender good enough?

Maybe you’re using Windows Defender because your computer came with it preinstalled. It seems fine, but you’ve never looked at other options. Or maybe you have Windows Defender and your computer somehow got an infection anyways. Either way, here’s something to consider: Defender is one of the most targeted security programs by cybercriminals. And there are whole categories of threats that Windows Defender doesn’t protect against.

The majority of threats detected today are found using signature-less technologies, but there are several other methods of malware detection that, when layered together, offer optimal protection over Windows Defender. Malwarebytes Premium, for example, uses a layered approach to threat detection that includes heuristic analysis technology as just one of its components. Other major components include ransomware protection, web protection, and anti-exploit technology.

Do Mac and mobile devices need anti-malware?

In 2019 for the first time ever, Macs outpaced Windows PCs in number of threats detected per endpoint. Over the last few years, Mac adware has exploded, debunking the myth that Macs are safe from cyberthreats. While Macs’ built-in AV blocks some malware, Mac adware has become so aggressive that it warrants extra anti-malware protection.

Meanwhile, Mac’s mobile counterpart, the iPhone, does not allow outside anti-malware programs to be downloaded. (Apple says its own built-in iOS protection is enough.) However, there are some privacy apps, web browser protection, and scam call blockers users can try for added safety.

As for Android, malware attacks from threats, such as adware, monitoring apps, and other potentially unwanted programs (PUPs) are more common. At best, PUPs serve up annoying ads you can’t get rid. At worst, they’ll discretely steal information from your phone.

Also, because the Android environment allows for third-party downloads, it’s a bit more vulnerable to malware and PUPs than the iPhone. So we recommend a good anti-malware solution for your Android device as well.

How can I remove malware?

Malware detection is the important first step for any cybersecurity solution. But what happens next? If you get a malware infection on one of your devices, the good news is you can easily remove it. The process of identifying and removing cyberthreats from your computer systems is called “remediation.”

To conduct a thorough remediation of your device, download an anti-malware program and run a scan. Before doing so, make sure you back up your files. Afterwards, change all of your account passwords in case they were compromised in the malware attack. And if you’re dealing with a tough infection, you’re in luck: Malwarebytes has a rock-solid reputation for removing malware that other programs can’t even detect let alone remove.

If you need to clean an infected computer now, download Malwarebytes for free, review these tips for remediation, and run a scan to see which threats are hiding on your devices.

How do I protect against malware?

Yes, it’s possible to clean up an infected computer and fully remove malware from your system. But the damage from some forms of malware, like ransomware, cannot be undone. If it’s encrypted your files and you haven’t backed them up, the jig is up. So your best defense is to beat the bad guys at their own game—by preventing infection in the first place.

There are a few ways to do this. Keeping all devices updated with the latest software patches will block threats designed to exploit older vulnerabilities. Automating backups of files to an encrypted cloud storage platform won’t protect against ransomware attacks, but it will ensure that you needn’t pay the ransom to retrieve your files. Training on cybersecurity best practices, including how to spot a phishing attack, tech support scam, or other social engineering technique, also helps stave off insider threats.

However, the best way to prevent malware infection is to use an antivirus/anti-malware program with layered protection that stops a wide range of cyberthreats in real time—whether it’s a malicious website or a brand-new malware family never before seen “in the wild.”

But if you have antivirus already and threats are getting through, maybe it’s time to move on to a program that’ll “just fix your computer” so you can stop worrying about malware detection and start…participating in distance learning classes? Ordering groceries? Having your virtual doctor’s appointment? Developing a vaccine? Literally anything else.


Philip Christian

Cybersecurity writer at Malwarebytes. Types his missives on a manual typewriter.