1. Hacker

2. Hacker, Cracker?! • Are they the same?

3. No!!!

4. Hacker • programmers • intensely interested in the arcane and recondite workings of any computer operating system. • advanced knowledge of operating systems and programming languages. • know of holes within systems and the reasons for such holes. Hackers constantly seek further knowledge, freely share what they have discovered, and never, ever intentionally damage data.

5. Cracker • breaks into or otherwise violates the system integrity of remote machines, with malicious intent. • having gained unauthorized access, destroy vital data, deny legitimate users service, or basically cause problems for their targets. • can easily be identified because their actions are malicious.

6. Tools for hacking Scanners Trojan Horses Packet sniffing Password Cracker

7. Scanners • In Internet security, no hacking tool is more celebrated than the scanner. • good TCP port scanner is worth a thousand user passwords.

8. What Is a Scanner? • program • automatically detects security weaknesses in a remote or local host. • important to Internet security • reveal weaknesses in the network

9. How Do Scanners Work? • Every PC has 65535 port • TCP port scanners programs which • attack TCP/IP ports and services (Telnet or FTP, for example) and record the response from the target. • glean valuable information about the target host

10. What Will a Scanner Tell Me? • reveal certain inherent weaknesses within the target host. • These might be key factors in implementing an actual compromise of the target's security.

11. What Won't a Scanner Tell Me? • A step-by-step method of breaking in • The degree to which your scanning activity has been logged

12. Password Cracker • Program • can decrypt passwords or otherwise disable password protection. • Most of them need not decrypt anything.Real encrypted passwords cannot be reverse-decrypted.

13. Packet sniffing • program • captures data from information packets as they travel over the network. • data may include • user names, passwords, and proprietary information that travels over the network in clear text. • With perhaps hundreds or thousands of passwords captured by the packet sniffer, intruders can launch widespread attacks on systems. • Installing a packet sniffer does not necessarily require administrator-level access.

14. Trojan horse • program • containing hidden functions • can exploit the privileges of the user [running the program], with a resulting security threat. • does things that the program user did not intend • rely on users to install them • can be installed by intruders who have gained unauthorized access by other means.

15. What do Trojan horses do? • can do anything that the user executing the program has the privileges to do.Include: • deleting files that the user can delete • transmitting to the intruder any files that the user can read • changing any files the user can modify installing viruses • installing other Trojan horses

16. installing other programs with the privileges of the user • programs that provide unauthorized network access • executing privilege-elevation attacks

17. Example of Trojans • Back Orifice • NetBus

18. The most common attack DDoS

19. DDoS • DDoS(distributed denial-of-service) • DoS • is called a attack(denial-of-service DoS) • causes your computer to crash or to become so busy processing data that you are unable to use it

20. Ping of Death • Sending too large ping request. • Fragmentation allow to send this large packet. • When packet re-combine,this will overload the buffer.

21. SYN Flooding • Send tons of SYN(SYNchronize) request to server • When server send SYN-ACK(ACKnowledge) response,it can’t send the last acknowledgment request. • Result- use up the network buffer.

22. Contributes of hacker?? • Linux is written by hacker!!

23. The End