The document discusses various network security techniques including eavesdropping, cryptanalysis, and password pilfering. It also covers common tools and techniques used for denial of service attacks, malicious software, and encryption basics. Specific methods mentioned are social engineering, guessing common passwords, cryptanalysis using math and powerful computers, and types of buffer overflow attacks.

1. Network Security
Present by Khoa.NK

2. Common technics
Eavesdropping
- Put devices and/or softwares in middle layer
- Easier in wireless network
- No-way to prevent in the public networks
- Encrypt data

3. Common technics
Cryptanalysis
- Find information from encrypted data
- Use math methodology and high
performance machines
- Encrypt data with un-structure algorithm
- Use complex password for route-force attack

4. Common technics
Password Pilfering
- Guessing
- Social engineering
- Dictionary
- Password sniffing

5. Common technics
Guessing: 10 passwords most common in the
world by PC Magazine)
Password 123456 qwerty abc123 letmein
monkey myspace1 password1 blink182 (the
user's own first name)

6. Common technics
Social engineering: use social skill to find
information
- impersonate
- physing via email, website

7. Common technics
Identity Spoofing

8. Common technics
Buffer-overflow
- strcat(), strcpy(), sprintf(), vsprintf(), bcopy(),
get(), scanf(),..

9. Common technics
DoS and DDoS
- Type
- Smurf
- Buffer Overflow attack
- Ping of dead
- SYN attack
Tools: Jolt2, Bubonic.c, Land and LaTierra,
Targa, Blast20, Crazy Pinger, Some Trouble,...

10. Common technics
Malicious Softwares
- Virus
- Worms
- Trojan
- Logic bomb
- Backdoor
- Spyware
- Keylogger

11. Encryption
- plaintext
- cyphertext
- key
c = E(m, k)
m = D(c, k)