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.

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🔑 Key Functions of Antivirus:

Function	Description
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

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⚙️ How Antivirus Works:

1. Scanning — Examines files, software, and system areas.

2. Detection — Uses signature-based and behavior-based (heuristics) techniques to identify threats.

3. Alerting — Notifies the user if a threat is found.

4. Quarantine or Removal — Isolates or deletes the infected file to prevent harm.

5. Automatic Updates — Regular updates to keep up with new threats.

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📊 Types of Malware Antivirus Protects Against:

Malware Type	Description
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

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🧠 Types of Antivirus:

Type	Description	Example
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

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🌐 Popular Antivirus Software:

Antivirus Name	Type	Notes
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

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🚨 Antivirus Techniques for Detection:

Method	Description
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

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✅ Example of How Antivirus Protects You:

1. You download an email attachment.

2. Antivirus scans the attachment before you open it.

3. If it contains malware (like ransomware), the antivirus alerts you.

4. The malware is quarantined or deleted to prevent infection.

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🚀 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.

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✅ Summary Table:

Feature	Description
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