SSC CGL Preparation – Day 16

Computer Basics: Network and Information Security Threats

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🔷 What is Network and Information Security?

• Network Security: Protects the infrastructure and data in a network from unauthorized access, misuse, or theft.
• Information Security: Ensures the confidentiality, integrity, and availability of data.

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🔷 Common Network and Information Security Threats

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🔹 1. Malware

• Short for Malicious Software.
• Types:
  • Virus – Attaches to programs/files and spreads.
  • Worm – Replicates and spreads over networks without user action.
  • Trojan Horse – Appears legitimate but contains harmful code.
  • Ransomware – Locks/encrypts data and demands payment to unlock.
  • Spyware – Secretly collects user data.
  • Adware – Displays unwanted ads, often tracks user behavior.

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🔹 2. Phishing

• Fraudulent emails/websites that mimic legitimate ones to steal:
  • Usernames
  • Passwords
  • Bank details
• Often contains urgent messages or fake links.

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🔹 3. Denial of Service (DoS) Attack

• Overloads a server/network, making it unavailable.
• DDoS (Distributed DoS): Attack from multiple sources at once.

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🔹 4. Man-in-the-Middle (MitM) Attack

• Hacker intercepts communication between two systems.
• Can read or alter the transmitted data.

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🔹 5. SQL Injection

• Hacker enters malicious SQL code in web forms to access or manipulate databases.

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🔹 6. Brute Force Attack

• Automated attempt to guess passwords using multiple combinations.

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🔹 7. Zero-Day Exploit

• Targets vulnerabilities unknown to the software vendor.
• Extremely dangerous as there’s no patch available.

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🔹 8. Social Engineering

• Manipulating people to reveal confidential information (e.g., through impersonation).

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🔹 9. Keylogger

• Records every keystroke on the keyboard.
• Used to steal passwords, personal info.

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🔹 10. Spoofing

• Disguising as a trusted source to trick users.
  • Email spoofing
  • IP spoofing
  • Website spoofing

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🔷 Effects of Security Threats

Impact	Description
🔓 Data Breach	Confidential data gets leaked
💰 Financial Loss	Unauthorized transactions, ransom payments
⚠️ Identity Theft	Attacker uses stolen personal info
🛑 Service Disruption	Websites or networks become unavailable
💼 Reputation Damage	Organization loses trust

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🔷 Basic Prevention Methods (Covered in Day 17)

• Using firewalls and antivirus.
• Strong passwords and two-factor authentication.
• Avoiding suspicious links/emails.
• Regular software updates and backups.

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🔷 Important Terms to Remember

Term	Meaning
Virus	Needs a host file to spread
Worm	Spreads independently over networks
Trojan	Disguised as legitimate software
Ransomware	Encrypts data, demands payment
Spyware	Secretly monitors user activity
Phishing	Tricks users into revealing private info
DDoS	Distributed attack causing system failure
Brute Force	Guessing password combinations
SQL Injection	Hacking databases using code injections
Keylogger	Records keystrokes
Zero-Day Attack	Exploits unknown vulnerabilities

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🔷 For SSC CGL – Focus Points

✅ Difference between malware types
✅ Meaning of phishing, spoofing, ransomware
✅ Understanding DoS/DDoS and social engineering
✅ Recognize basic security terminology