Viruses
What is Viruses?
A virus is a type of malicious software that attaches itself to a legitimate file, program, or boot process and spreads when the infected host is executed or accessed.
Examples
- A user runs an infected executable, and the virus copies its code into other files on the same system.
- A macro virus spreads through office documents when recipients open the file and enable its embedded code.
Discover 🔎
The word virus is often used casually to describe almost any malware, but in security it has a more specific meaning. A virus is not simply malicious code sitting on a system. It is malware that spreads by attaching itself to something else and then using that host to reproduce.
That characteristic makes viruses important to understand. They depend on execution and replication. When the infected file, document, or boot component is used, the virus gains an opportunity to run and copy itself further. The damage may come from the payload, but the defining feature is the way the malware spreads.
Summary 📝
A virus is malware that spreads by attaching itself to another file, program, document, or boot component and reproducing when that host is used. Its defining trait is infection-based replication rather than independent network spreading. Viruses remain an important concept because they show how malicious code can abuse trust in ordinary files and use routine execution as the path to wider compromise.
Tip: The interactive version includes progress tracking, decks, and premium deep dives.