Unit-4-LOS.pdf

Unit - 4
security and protection
PREPARED BY:
MR. HARISH I. RATHOD
DEPARTMENT OF INFORMATION TECHNOLOGY.
GOVERNMENT POLYTECHNIC, HIMATNAGAR.
LINUX OPERATING SYSTEMS (4331602)

Unit Outcome
• .
2
Unit-4 Security and Protection
Justify the need of security
measures in Operating
System
Identify various program
threats and system threats
in OS
Justify the need of
protection mechanism in OS.
Summarize various
protection domain.

Exam Point of View
• .
3
Unit Name Teaching Hrs. R-Level U-Level A-Level Total Marks
Security and
Protection
08 08
Marks
06
Marks
00
Marks
14

Lecture Outcome
• .
4
..
Explain
Security in
Operating
System
Lecture
Outcome

Introduction
• The process of ensuring OS availability, confidentiality,
integrity is known as operating system security.
• Security is refers to providing safety for computer system
resources like software, CPU, memory, disks, etc.
• It can protect against all threats, including viruses and
unauthorized access.
• It can be enforced by assuring the operating system's
integrity, confidentiality, and availability.
5
Q: Define operating system security

Security measures
• To protect the system, security measures can be taken at the
following levels:
• Physical.
• Human.
• Operating Systems.
• Networking Systems.
6
Q: List out and explain security measures

Security measures
• Physical:
• The sites containing computer systems must be physically
secured against armed and malicious intruders.
• Workstations must be carefully protected.
7

Security measures
• Human:
• Only appropriate users must have the authorization to access
the system.
• Phishing and Dumpster Diving must be avoid.
• Phishing: Collecting confidential information.
• Dumpster Diving: Collecting basic information so as to gain
unauthorized access.
8

Security measures
• Operating System:
• Operating system must protect itself from accidental or
purposeful security breaches.
9

Security measures
• Networking system:
• Almost all of the information is shared between different
system via a network.
• Intercepting these data could be just as harmful as breaking
into a computer.
• Hence, network should be properly secured against attacks.
10

System Authentication
• It refers to identifying each user of the system and
associating the executing programs with those users.
• The OS ensures that a user who is running a particular
program is authentic.
11
Q: Explain System Authentication

• The OS generally identifies/authenticates users using
following three ways:
• Username/Password.
• User key/card.
• Biometric based.
12

• Username/Password: User need to enter a registered
username and password with OS.
• User key/card: User need to punch card in card slot, or
enter key to login into the system.
• Biometric based: User need to pass his/her attribute via
designated input device used by operating system to login
into the system.
13

Threats
• Mainly two types of threads:
• Program threats.
• System threats.
14

Threats
Program Threats
• The OS’s processes and kernel carry out the specified
task as directed.
• Program Threats occur, when a user program causes these
processes to do malicious operations.
• The common example is that when a program is installed
on a computer, it could store and transfer user credentials
to a hacker.
• There are various program threats.
• Some of them are as follows:.
15
Q: Define program threats

Threats
Program Threats
• There are various program threats.
• Some of them are as follows:
• Virus.
• Trojan Horse.
• Logic Bomb.
• Trap Door.
16
Q: List out and explain program threats

Threats
Program Threats
• Virus:
• A virus may replicate itself on the system.
• Viruses are extremely dangerous.
• It can modify/delete user files as well as crash computers.
• A virus is a little piece of code that is implemented on the
system program.
17

Threats
Program Threats
• Virus:
• As the user interacts with the program,
• The virus becomes embedded in other files and programs,
potentially rendering the system inoperable.
18

Threats
Program Threats
• Trojan Horse:
• This type of application captures user login credentials.
• It stores them to transfer them to a malicious user who
can then log in to the computer and access system
resources.
19

Threats
Program Threats
• Logic Bomb:
• A logic bomb is a situation in which,
• Software only misbehaves when particular criteria are met;
• Otherwise, it functions normally.
20

Threats
Program Threats
• Trap Door:
• A trap door is,
• When a program that is supposed to work as expected has
a security weakness in its code that allows it to do illegal
actions without the user's knowledge.
21

Threats
System Threats
• System threats are described as the misuse of system
services and network connections to cause user problems.
• These threats may be used to trigger the program threats
over an entire network, known as program attacks.
• System threats make an environment in which OS resources
and user files may be misused.
• There are various system threats. Some of them are as
follows.
22
Q: Define System threats

Threats
System Threats
• There are various system threats.
• Port Scanning.
• Worm.
• Denial of service.
23
Q: List out and explain System threats

Threats
System Threats
• Port Scanning:
• It is a method by which the cracker determines the
system's vulnerabilities for an attack.
• It is a fully automated process that includes connecting to a
specific port via TCP/IP.
• To protect the attacker's identity, port scanning attacks are
launched through Zombie Systems.
24

Threats
System Threats
• Warm:
• The worm is a process that can choke a system's
performance by exhausting all system resources.
• A Worm process makes several clones,
• Each clone consuming system resources and preventing all
other processes from getting essential resources.
• Worm processes can even bring a network to a halt.
25

Threats
System Threats
• Denial of service:
• Denial of service attacks usually prevents users from
legally using the system.
• For example,
• If a denial-of-service attack is executed against the browser's
content settings, a user may be unable to access the internet.
26

Threats to OS
• Malware.
• Network intrusion.
27

Ensure OS security
• Various ways to ensure.
• Authentication. (Username/Password, Biometric, card and
key)
• One Time Password. (Secret key, Random number, N/w
password)
• Firewalls.
• Physical security.
28

Policies and Procedure
• Various policies may be implemented based on the
organization.
• In general,
• An OS security policy is a document that specifies the
procedures for ensuring that the operating system
maintains a specific level of integrity, confidentiality, and
availability.
29
Q: Explain Operating System security policies and procedure

• As we know, OS Security protects systems and data from
worms, malware, threats, etc.
• Security policies handle all preventative activities and
• Procedures to ensure an operating system's protection,
including steal, edited, and deleted data.
30

• As OS security policies and procedures cover a large area,
there are various techniques to addressing them.
• 1) Installing and updating anti-virus software.
• 2) Ensure the systems are patched or updated regularly.
31

• 3) Implementing user management policies to protect user
accounts and privileges.
• 4) Installing a firewall and ensuring that it is properly set to
monitor all incoming and outgoing traffic.
32

Protection mechanism
• System protection refers to the mechanisms implemented
by the operating system,
• To ensure the security and integrity of the system.
• It involves various techniques,
• To prevent unauthorized access, misuse, or modification
of the operating system and its resources.
33

• Protection is especially important in a multiuser
environment,
• When multiple users use computer resources such as CPU,
memory, etc.
• It is the Operating system's responsibility to offer a
mechanism that protects each process from other
processes.
34

• In a multiuser environment,
• All assets that require protection are classified as objects,
and
• Those that wish to access these objects are referred to as
subjects.
• The OS grants different 'access rights' to different
subjects.
35

• There are several ways in which an OS can provide system
protection:
• User authentication.
• Access Control.
• Encryption.
• Firewall
• Antivirus Software.
• System updates and patches.
36

System Protection
• Protection refers to a mechanism which controls the
access of programs, processes, or users to the resources
defined by a computer system.
37
Q: Define system protection

Need of Protection
• To prevent the access of unauthorized users.
• To ensure that,
• Each active programs or processes in the system uses
resources only as the stated policy.
• To improve reliability by detecting latent errors.
38
Q: Justify need of protection mechanism in OS

Protection Domain
• Various domains of protection in OS are as follows:
• Process's protected domain:
• The protection policies restrict each process's access to its
resource handling.
• A process is allowed to use only the necessary resources
with time constraints.
39
Q: Explain protection domian

Protection Domain
• Process and object:
• They are abstract data types in a computer system, and
• These objects have operations that are unique to them.
• A domain component is defined as:.
40
<object, {set of operations on object}>

Protection Domain
• Collection of object:
• Each domain comprises a collection of objects.
• The operations may be implemented on objects.
• A domain could be made up of only one process,
procedure, or user.
• If a domain is linked with a procedure, then changing the
domain would mean changing the procedure ID.
• Objects may share one or more common operations..
41

Protection Domain
• ..
42

Introduction
• .
43

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