Malware (malicious software) is any program or code created to cause harm to a computer, network, or user. It is the umbrella term covering all hostile software regardless of how it is delivered or what it does once installed.

Common Types of Malware

TypeWhat It DoesHow It Spreads
VirusAttaches to files and replicates when files are openedInfected files, downloads, email attachments
TrojanDisguises itself as legitimate software to gain accessFake downloads, cracked software
RansomwareEncrypts your files and demands payment to unlock themPhishing emails, malicious links
SpywareMonitors your activity and sends data to attackersBundled with free software, drive-by downloads
KeyloggerRecords every keystroke including passwordsTrojans, physical device access
RootkitHides deep in the OS to avoid detectionExploits, infected installers
AdwareDisplays intrusive ads, may redirect browserBundled with free software
WormSelf-replicates across networks without user actionNetwork vulnerabilities

How to Protect Yourself

  • Keep your OS and software updated — patches close the vulnerabilities malware exploits
  • Do not open email attachments or click links from unknown senders
  • Only download software from official sources
  • Use a reputable antivirus or endpoint protection tool
  • Back up your data regularly so ransomware cannot hold you hostage
  • Use a standard (non-admin) user account for everyday tasks

Warning Signs of Infection

  • Device is significantly slower than normal
  • Unexpected pop-ups or browser redirects
  • Programs launching or closing on their own
  • High network traffic when you are not actively browsing
  • Antivirus has been disabled without your action

People Also Ask

Can malware affect iPhones or Macs?
Yes, though less commonly than Windows. Macs have been targeted by adware and spyware. iPhones are largely protected by the App Store sandbox, but jailbroken devices are at much higher risk. No platform is immune.
How do I remove malware?
Boot into safe mode, run a reputable malware scanner, remove detected threats, and change any passwords you may have entered while infected. For severe infections (rootkits, ransomware), a full OS reinstall is often the safest option.

Related: Data breach | Brute force attacks | Breach Check