Antivirus
✅ What is Antivirus?
An Antivirus is software designed to detect, prevent, and remove malicious software (malware) such as viruses, worms, trojans, ransomware, spyware, and other harmful programs from computers and networks.
➡️ Purpose:
Protect devices and data from malware infections.
Prevent unauthorized access and data breaches.
Detect and remove existing threats.
🔑 Key Functions of Antivirus:
Malware Detection
Identifies malicious files or programs
Real-time Protection
Continuously monitors the system for threats
Scanning (On-demand & Scheduled)
Scans files, programs, and system areas for malware
Threat Removal
Quarantines or deletes infected files
Automatic Updates
Keeps virus definitions and threat database up-to-date
Web Protection
Blocks malicious websites and phishing attempts
Email Scanning
Scans email attachments and links for threats
Behavior Analysis (Heuristic)
Detects unknown malware based on suspicious behavior
⚙️ How Antivirus Works:
Scanning — Examines files, software, and system areas.
Detection — Uses signature-based and behavior-based (heuristics) techniques to identify threats.
Alerting — Notifies the user if a threat is found.
Quarantine or Removal — Isolates or deletes the infected file to prevent harm.
Automatic Updates — Regular updates to keep up with new threats.
📊 Types of Malware Antivirus Protects Against:
Virus
Self-replicating code that spreads and damages files
Worm
Malware that spreads over networks without user action
Trojan Horse
Malware disguised as legitimate software
Spyware
Secretly monitors user activity and steals data
Ransomware
Locks/encrypts files and demands payment
Adware
Unwanted ads that can also carry malware
Rootkits
Stealthy malware that hides deep in system
🧠 Types of Antivirus:
Standalone Antivirus
Protects individual devices (PC, mobile)
Windows Defender, Avast Free Antivirus
Internet Security Suites
Includes antivirus + firewall + web protection
Norton 360, Kaspersky Internet Security
Enterprise Antivirus
Centralized protection for corporate networks
McAfee Endpoint Security, Symantec Endpoint Security
Cloud-based Antivirus
Uses cloud for real-time scanning and updates
Sophos Home, Panda Cloud Antivirus
🌐 Popular Antivirus Software:
Windows Defender
Built-in (Free)
Comes with Windows, basic but effective
Norton Antivirus
Paid
Includes VPN, password manager
Kaspersky Antivirus
Paid
High detection rates, privacy tools
Bitdefender
Paid
Lightweight, powerful real-time protection
McAfee
Paid
Includes identity and privacy protection
Avast
Free & Paid
Popular free option, some advanced tools
Sophos Home
Free & Paid
Good for families, business-level protection
🚨 Antivirus Techniques for Detection:
Signature-based Detection
Matches files against known malware database
Heuristic-based Detection
Detects unknown malware by analyzing behavior
Behavioral Analysis
Monitors real-time activities for suspicious actions
Sandboxing
Runs suspicious files in isolated environment to check behavior
Cloud-based Analysis
Uses cloud to analyze files quickly and accurately
✅ Example of How Antivirus Protects You:
You download an email attachment.
Antivirus scans the attachment before you open it.
If it contains malware (like ransomware), the antivirus alerts you.
The malware is quarantined or deleted to prevent infection.
🚀 Simple Analogy:
Antivirus is like a security guard for your computer:
Scans visitors (files, programs) before letting them in.
Watches what's happening in real-time.
Stops and removes anything dangerous.
Updates its knowledge (virus database) to recognize new threats.
✅ Summary Table:
Detects malware
Identifies viruses, worms, trojans, ransomware
Real-time protection
Stops threats before they cause harm
Removes infections
Deletes or quarantines threats
Updates regularly
Keeps up with new malware
Types
Standalone, security suites, enterprise
Last updated