Network security involves more than just technical aspects like firewalls and intrusion detection - it also requires policies, procedures, an understanding of legal issues and human behavior. There are many types of attacks like spoofing, denial of service, and distributed denial of service attacks. Firewalls and antivirus software can provide security against threats like Trojans and hackers by preventing unauthorized access. Common steps attackers take include reconnaissance, scanning systems to find vulnerabilities, gaining access by exploiting them, maintaining future access by installing backdoors, and covering their tracks.

1. Lecture 19
Hacking

2. WHAT IS NETWORK SECURITY?
• Security is much larger than just packets, firewalls,
and hackers. Security includes:
– Policies and procedures
– Liabilities and laws
– Human behavior patterns
– Corporate security programs and implementation
– Technical aspects- firewalls, intrusion detection systems,
proxies, encryption, antivirus software, hacks, cracks, and
attacks
• Understanding hacking tools and how attacks are
carried out is only one piece of the puzzle.
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3. ATTACKS
 THERE ARE MANY TYPES OF ATTACKS
• SPOOFING ATTACK
• TELNET BASED ATTACK
• DOS (Daniel of service) ATTACK
• PING OF DEATH
• DISTRIBUTED DOS ATTACK
• MAILBOMBS

4. NEED FOR SECURITY
 SOME EXELLENT SOFTWARE CAN PROVIDE
YOU BEST SECURITY
 LIKE
• TROJAN
• FIREWALL

5. TROJAN
 WINDOWS TROJANS ARE SMALL ASPECT OF
WINDOWS SECURUTY
 TROJAN IS UNOTHORIZED PROGRAM
CONTAINED WITHIN A LEGIMATE PROGRAM
 THIS PROGRAM PERFORMS FUNCTION
UNKNOWN BY USER

6. FIREWALL
 FIREWALL IS ANY DEVICE USED TO PREVENT
OUTSIDERS FROM GAINING ACCESS TO YOUR
NETWORK
 TYPES OF FIREWALLS
• PACKET FILTER
• APPLICATION PROXY
• PACKET INSPECTION

7. Common Steps for Attackers
Reconnaissance
– Intelligent work of obtaining information either
actively or passively
– Examples:
• Passively: Sniffing Traffic, eavesdropping
• Actively: Obtaining data from American Registry for
Internet Numbers (ARIN), whois databases, web sites,
social engineering
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8. Common Steps for Attackers
• Scanning
– Identifying systems that are running and services
that are active on them
– Examples: Ping sweeps and port scans
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9. Common Steps for Attackers
• Gaining Access
– Exploiting identified vulnerabilities to gain
unauthorized access
– Examples: Exploiting a buffer overflow or brute
forcing a password and logging onto a system
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10. Common Steps for Attackers
• Maintaining Access
– Uploading malicious software to ensure re-entry is
possible
– Example: Installing a backdoor on a system
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11. Common Steps for Attackers
• Covering Tracks
– Carrying out activities to hide one’s malicious
activities
– Example: Deleting or modifying data in a system
and its application logs
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