Security glossary
Twenty terms that appear constantly in security marketing, defined in plain English and without selling you anything. No product is mentioned on this page.
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Adware
Software that injects or redirects advertising. Rarely destructive, frequently bundled with something you did install on purpose, and often the visible symptom of a wider unwanted-software problem.
Behavioural detection
Watching what a running program does rather than what it looks like. Catches genuinely new malware, but only once the behaviour has started, so it contains as much as it prevents.
Brute force
Trying credentials repeatedly until one works. Defeated by rate limiting, by long unique passwords, and decisively by two-factor authentication.
Credential stuffing
Taking username and password pairs leaked from one breached service and trying them on others. It works only because passwords get reused, which is the entire argument for a password manager.
Drive-by download
Malware delivered by merely visiting a compromised or malicious page, exploiting an unpatched browser or plug-in. The reason browser updates are not optional.
End-to-end encryption
Encryption where only the two ends hold the keys, so the service carrying the message cannot read it. Distinct from transport encryption, where the provider can.
False positive
A clean file wrongly flagged as malicious. Independent laboratories count these alongside detection rates, because an over-eager scanner that quarantines your own work is its own kind of failure.
Firewall
Controls which network connections are permitted in or out. Present in every modern operating system and in your home router; a suite may add a friendlier interface to the same idea.
Heuristics
Structural analysis of code for traits malware tends to share. Generalises beyond the signature catalogue, at the cost of occasional false positives.
Keylogger
Software or hardware that records keystrokes to capture passwords and card numbers. Behavioural detection is the usual defence; two-factor authentication is what limits the damage.
Malware
The umbrella term for any software written to act against the interests of the person running it: viruses, worms, trojans, ransomware, spyware, some adware.
Phishing
A message engineered to make you hand over credentials, money or access, usually by manufacturing urgency and impersonating someone you trust. Still the single most effective attack technique in use.
Ransomware
Malware that encrypts your files and demands payment for the key. The only reliable answer is an offline or otherwise isolated backup that you have actually tested restoring from.
Real-time protection
Continuous inspection of files as they are downloaded, opened or executed, as opposed to a scan you start yourself.
Sandbox
An isolated environment in which untrusted code runs without reaching the rest of the system. The core of the mobile security model and of modern browser design.
Signature
A hash or byte pattern that identifies a specific known piece of malware. Fast and precise; powerless against anything not yet catalogued.
Social engineering
Attacking the person rather than the machine. No product prevents it; a habit of verifying through a separate channel does.
Two-factor authentication (2FA)
Requiring a second proof of identity beyond the password. An app-generated code or a hardware key is materially stronger than an SMS, which can be intercepted or redirected by SIM swapping.
VPN
Encrypts your traffic to an exit server. Useful on networks you do not control and for hiding your address from the sites you visit. It does not make you anonymous, and it moves your trust to the VPN operator rather than removing the need for it.
Zero-day
A vulnerability exploited before a patch exists. Signature detection cannot help by definition; behavioural monitoring and prompt patching once a fix ships are what limit the window.
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