Notes
🦠 Malware
- Definition: Malicious software that acts without user’s knowledge and alters computer operations.
- Payload: The destructive event malware is designed to deliver.
- Symptoms: Slow performance, full storage, unusual messages, system property changes, unexpected shutdowns.
🧩 Types of Malware
- Virus: Program written to damage data; attaches to files and activates on certain events.
- Worm: Self-replicating malware that consumes system resources.
- Trojan Horse: Disguised as a friendly program but destroys data.
- Rootkit: Hides in a computer, allows remote control.
- Logic Bomb: Dormant until triggered by a specific date/event.
- Adware: Displays unwanted ads, may lead to infected sites.
- Spyware: Secretly collects user information.
- Keyloggers: Record keystrokes to steal sensitive data.
- Ransomware: Locks system and demands payment to restore access.
🧬 Types of Viruses
- File Infector: Infects program files, spreads when executed.
- Boot Sector Virus: Attaches to boot sector, very dangerous.
- Macro Virus: Infects files with macros (automated tasks).
- E-mail Virus: Spreads via infected email attachments.
- Executable File Virus: Infects executable (.exe) files.
Examples:
- Sweeper: Fake antivirus that changes system files.
- Sleeper: Steals personal/financial info, targets large networks.
- Alabama: Infects executable files, manipulates file names.
📥 Sources of Viruses
- E-mail attachments
- Internet downloads
- Software distribution via infected media
🛡️ Antivirus Programs
- Definition: Detect and remove viruses; use virus signatures (patterns of virus code).
- Working: Infected files are removed or quarantined (isolated).
- Virus Hoax: Fake warnings about non-existent viruses.
Popular Antivirus Software: Norton, McAfee, Kaspersky, AVG, TotalAV, Quick Heal.
⚠️ Precautions Against Malware
- Do not boot with removable media inserted.
- Avoid opening unexpected email attachments.
- Verify attachments even from known contacts.
- Delete suspicious messages.
- Never share sensitive data via email.
- Download only from trusted websites.
- Install and update antivirus regularly.
- Scan all downloads before use.
