5 Signs of a Malware Infection and How to Get Rid of It

The internet is an integral part of life today, which means that nearly everyone faces the threat of malware infections.

Over time, malware has grown increasingly sophisticated, fed by the creativity of black hat hackers seeking to devise ever more damaging and difficult-to-detect viruses, worms, Trojans, spyware, adware, ransomware, and other forms of destructive code.

If you know what to look for, there are signs that your computer may be infected with malware. There are also reliable methods to clean up the infections and preventative strategies to keep your computer from becoming compromised again in the future.

Common Signs of a Malware Infection

The first step to beating malware is knowing if and when your computer has been infected. Here are five ways you can quickly check if there’s a malware infection on your computer.

1. Your Computer Runs Slowly and Takes Longer to Start

A slow-running computer is one possible sign of an infection.

If your computer used to start up quickly and run its applications with ease, be concerned if it suddenly runs very slowly and even simple tasks take a long to time execute.

A slowdown can also result from low storage, aging hardware, or software problems, so it does not confirm malware on its own.

2. Inexplicable Freezes or Crashes

If your computer freezes for no clear reason, stops working and then restarts all on its own, malware could be one possible cause, but hardware or software problems can cause the same symptoms.

A blue screen by itself does not show that malware caused the problem.

3. Suspicious Pop-up Ads or Security Warnings

Pop-up ads are notoriously annoying. They are so widely hated that many browsers now include pop-up blockers so that you do not have to deal with them. Therefore, if you suddenly receive a large number of pop-up ads, adware or other unwanted software may be responsible, though pop-ups alone do not prove infection.

You may also get sudden, scary warnings which declare that you have malware on your system, offer you antivirus software and urge you to take immediate action. Ironically, warnings like this are actually a way for hackers to get malware into your system or to steal your personal information.

Do not call phone numbers in pop-ups or install software they advertise. Close the page and use a security program from a source you trust.

4. Ransom Demands

Certain types of malware, called ransomware, can be used to hold your network, your computer, or your files for ransom.

A hacker may, for example, use ransomware to get into your system, encrypt all of your files and prevent you from accessing them unless you pay a ransom.

If files suddenly become inaccessible or you see a ransom note, treat it as an urgent security incident. Do not assume that paying will restore your files. Stop using the device for sensitive logins and contact a trusted IT professional; for a work computer, notify your organization’s security team.

A fake law-enforcement warning demanding a fine is a scam, not proof that files have been encrypted.

5. Everything Appears Normal

Malware can sometimes run quietly without obvious symptoms. Spyware may monitor activity or capture sensitive information without disrupting normal computer use.

A computer that appears normal does not rule out malware, but normal behavior alone is not a reason to assume an infection.

What to Do When You Have Malware

If you’re suspicious you do indeed have malware on your computer, what can you do to remove it? More importantly, what precautions can you take to keep your files safe and your machine from being attacked again in the future?

If you suspect malware, take these steps:

• Stop entering passwords or other sensitive information on the suspected device. Use a different, trusted device to secure accounts if needed.
• Update your security software and run a full scan. Follow the program’s instructions to quarantine or remove detected threats. For Windows, Microsoft explains how to troubleshoot scans and run Microsoft Defender Offline here. 
• Change passwords for accounts used on the device, starting with email and financial accounts, and turn on multifactor authentication where available. 
• If threats return, the scan fails, or files are encrypted, contact your device manufacturer or a trusted IT professional. Get advice before wiping the computer or restoring files from backup.

How to Reduce the Risk of Malware Infection

Install Antivirus Software

Security software remains useful for detecting and removing many kinds of malware, but no tool catches everything. Keep trusted security software updated and run scans as recommended.

Install Software Updates

Malware often works by exploiting holes in your operating system software or in other software that you have installed.

Just as hackers are busy discovering security flaws and writing malware to exploit them, cybersecurity professionals are at work patching up the security holes that hackers discover.

Keep your operating system, browser, and applications updated to install available security fixes. Download software from official vendor sites and be cautious with unexpected links, attachments, and unfamiliar downloads. 

Use Encryption and Strong Passwords

Passwords are one of the main pieces of information that hackers look to steal so that they can get into your system. If you have a simple password, then a hacker using a password dictionary will probably be able to crack it without much effort.

This is why it’s important to come up with long, unique passwords for each of your devices or accounts. Furthermore, you should encrypt as much of your computer activity as possible, especially files and communications to provide an additional layer of security.

Use a unique password for each account and enable multifactor authentication where available. If you suspect infection, change passwords from a different device you trust.

Be Rid of Malware Once and For All

If your computer shows several warning signs, run an updated security scan and secure your accounts from a trusted device. Get professional help if the threat persists, files are encrypted, or security tools will not run.

About the Author

Sam Bocetta Freelance Journalist

Sam Bocetta is a freelance journalist specializing in U.S. diplomacy and national security, with emphases on technology trends in cyberwarfare, cyberdefense, and cryptography.Previously, Sam worked as a security analyst for the DoD, and spent 30-plus years bolstering cyber defenses for the Navy. Much of his work involved penetration testing Navy ballistic systems. He also helped plan, manage and execute sophisticated "ethical" hacking exercises to identify vulnerabilities and reduce the risk posture of enterprise systems.Sam is now semi-retired and educates the public about security and privacy technology. He is currently working as part-time cybersecurity coordinator at assignyourwriter.co.uk.

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