Free demo · Information Security · Lesson 6 · Phase 2 · Clean systems

Antivirus, and a clean PC and phone

An antivirus is your guard: it checks files against known signatures, watches for suspicious behaviour and asks the cloud about new files. But the guard only works if the house has locks too.

🛡Microsoft Defender
🛡️
Quick scanChecking 41,208 files…
Real-time protectionOn
Virus definitionsUpdated today
Trojan:Win32/Wacatac in setup_crack.exeQuarantined
DetectionSignature + behaviour

Examples

Microsoft Defender (built into Windows 10/11, free) · Bitdefender · Norton · McAfee · ESET · Kaspersky · Quick Heal (Pune, India) · Malwarebytes for a second opinion · on Android, Google Play Protect. Pick one, keep it updated, never run two real-time scanners together.

  1. 1Updates on for the OS, browser and apps. Most mass attacks use holes that were already fixed.
  2. 2Official sources only: no pirated software or cracks, no .apk files from chats, no “free premium” apps.
  3. 3Check permissions: SMS, call-log and accessibility access are red flags for ordinary apps. Review apps monthly.
  4. 4Standard user account for daily work, firewall on, scan USB drives before opening them.
  5. ✓Backups 3-2-1: three copies, two kinds of storage, one off-site or in the cloud. Then ransomware cannot hold you hostage.
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  10. Enrol

Tip: press → or Space to step through, ← to go back, R to replay.

About this lesson

Antivirus software protects a device in three ways: signature scanning compares files with a database of known malware, heuristic and behavioural analysis flags programs that act suspiciously, and cloud reputation checks ask the vendor about new or rare files. Microsoft Defender is built into Windows 10 and 11 and is good enough for most home users; paid options include Bitdefender, Norton, McAfee, ESET, Kaspersky and India's Quick Heal, with Malwarebytes popular for second-opinion scans and Google Play Protect guarding Android. No scanner replaces hygiene: install updates promptly, use only official app stores, review app permissions, work from a standard user account with the firewall on, scan USB drives and keep 3-2-1 backups so ransomware cannot hold your data hostage. The full Phase 2 adds the signs of an infected device and a recovery procedure.

Key points

  • How antivirus detects malware
  • Antivirus examples for Windows and Android
  • Five hygiene rules for a clean PC and phone