What is a virus (malware)?
Definition
A virus (malware) is harmful code that infects a computer, runs without your permission and can damage your data or system. Malware is the wider term that also covers worms, Trojans and spyware.
- Category
- Attacks
- Also called
- computer virus, virus malware, malicious code
- Last updated
Malware is any software or firmware intended to perform an unauthorised process that harms the confidentiality, integrity or availability of a system. That is how NIST describes it in its glossary, listing "a virus, worm, Trojan horse, or other code-based entity that infects a host" as examples, along with spyware and some adware. A virus is one of those types.
Virus vs. malware
"Malware" is the whole family. "Virus" names one member, and in everyday speech people use it for all of them. If your antivirus warns of a threat, it usually means malware in general.
NIST also describes malware as a program inserted into a system, usually covertly, to compromise the victim's data, applications or operating system, or otherwise to annoy or disrupt the victim.
How it reaches you
The usual route is something you open or install: an email attachment, a download from an unofficial site, a link in a text message. Once the file runs, the code can copy itself, steal information or damage files.
A typical case: you get an email that looks like an invoice, you open the attached file, and nothing visible happens. In the background, software has been installed that records what you type.
Why it matters
Malware can capture passwords, read your messages, lock your files or use your device for other attacks. Stolen details can then end up used for identity theft or listed for sale.
Related types
- Worm spreads from device to device on its own.
- Spyware watches what you do and sends it on.
- Keylogger records what you type.
How to protect yourself
- 1
Keep your software up to date
Install updates for your operating system, browser and apps. Many infections use known flaws that updates close.
- 2
Don't open unexpected attachments or links
If an email or text isn't expected, don't open the file or tap the link. Contact the sender another way.
- 3
Install apps from official stores only
Downloads from unofficial sites are a common way malware gets onto a device.
- 4
Run reputable anti-malware
Use the built-in protection on your device or an anti-malware tool, and keep it on.
- 5
Change your passwords if you think you were infected
Do it from a clean device. Use unique passwords and turn on two-factor authentication.
See where your personal data is exposed
Serus finds it on data brokers and people-search sites and removes it.
Frequently asked
Is a virus the same as malware?
No. Malware is the broad category. A virus is one type, alongside worms, Trojan horses and spyware.
How do I know if I have malware?
Signs include a device that is suddenly slow, unexpected pop-ups, programs you didn't install, or accounts showing activity you didn't do. Some malware shows no signs, so run a scan.
Can phones get malware?
Yes. Phones can get malware, usually through malicious apps or links in messages.
Sources
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