1. Intrusion

2. Intruders
Intruders may be human attackers who manage to gain unauthorized access to computer resources or computer programs that seem to be useful, but secretly invade a system or a resource.
In general, three types of intruders can be distinguished.
Misfeasor
Masquerader
Clandestine User

3. Types of Intruders
Misfeasor : A legitimate user who accesses the data, programs, or resources for which such access is not authorized, or who is authorized for access but misuse privileges.
The user is mostly an insider.
Masquerader: An unauthorized individual user who penetrates a system’s access controls to exploit a legitimate user’s account.

4. Types of Intruders The user is more likely to be an outsider.
Clandestine User : An individual who seizes supervisory control of the system and uses this control to evade auditing and access controls, or to surpass audit collection.
The user can be an outsider or an insider.

5. Types of attacks
Backdoor
DOS
Spoofing
TCP/IP Hijacking
Exploits

6. Types of attacks Password guessing Brute Force Social Engineering
Eavesdropping
Buffer Overflow

7. Intrusion Techniques
Physical Intrusion : This type of intrusion assumes that an attacker has physical access to a machine.
System Intrusion : This type of hacking assumes that the attacker already has a low-privilege user account on the system.
If the system does not have the latest security patches, there is good chance for the attacker to gain additional administrative privileges.

8. Intrusion Techniques
Remote Intrusion : This type of hacking involves those attackers who do not have any special privilege and still attempt to break through a system remotely across the network.

9. Protecting Against Intruders
Password Protection
The simplest way of protecting user passwords is by keeping them encrypted on the disk so that nobody can attack the system by decrypting the password file.
This file should be hidden.
To break the password file, the attacker essentially has to guess the password of a user, hash it , and then compare it with entry in password file.

10. Protecting Against Intruders
The Vulnerability of Passwords
Exploitation of Weak Passwords
Exploitation of User Behaviour
Capture of Credentials in Transit.

11. Protecting Against Intruders
Strong Passwords
Make it Lengthy
Combine letters, symbols and symbols
Do not reveal them to others
Change passwords regularly