Operating System MCQs for Pakistan Govt Exams 2025

451

Which of the following is the least secure method of authentication?

a Key card

b fingerprint

c retina pattern

d Password

Medium

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452

Why is one time password safe?

a It is easy to generated

b It cannot be shared

c It is different for every access

d It is a complex encrypted password

Medium

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453

What does Light Directory Access Protocol (LDAP) doesn’t store?

a Users

b Address

c Passwords

d Security Keys

Medium

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454

What is characteristic of RADIUS system?

a It is essential for centralized encryption and authentication

b It works on Network layer to deny access to unauthorized people

c It provides centralized authentication mechanism via network devices

d It’s a strong File access system

Medium

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455

Which happens first authorization or authentication?

a Authorization

b Authentication

c Authorization & Authentication are same

d None of the mentioned

Medium

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456

What are the characteristics of Authorization?

a RADIUS and RSA

b 3 way handshaking with syn and fin

c Multilayered protection for securing resources

d Deals with privileges and rights

Medium

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457

What is not a best practice for password policy?

a Deciding maximum age of password

b Restriction on password reuse and history

c Password encryption

d Having change password every 2 years

Medium

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458

What is the breach of integrity?

a This type of violation involves unauthorized reading of data

b This violation involves unauthorized modification of data

c This violation involves unauthorized destruction of data

d This violation involves unauthorized use of resources

Medium

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459

What is breach of confidentiality?

a This type of violation involves unauthorized reading of data

b This violation involves unauthorized modification of data

c This violation involves unauthorized destruction of data

d This violation involves unauthorized use of resources

Medium

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460

What is theft of service?

a This type of violation involves unauthorized reading of data

b This violation involves unauthorized modification of data

c This violation involves unauthorized destruction of data

d This violation involves unauthorized use of resources

Medium

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461

What is breach of availability?

a This type of violation involves unauthorized reading of data

b This violation involves unauthorized modification of data

c This violation involves unauthorized destruction of data

d This violation involves unauthorized use of resources

Medium

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462

What is Trojan horse?

a It is a useful way to encrypt password

b It is a user which steals valuable information

c It is a rogue program which tricks users

d It’s a brute force attack algorithm

Medium

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463

What is trap door?

a IT is trap door in WarGames

b It is a hole in software left by designer

c It is a Trojan horse

d It is a virus which traps and locks user terminal

Medium

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464

Which of the following is not a characteristic of a virus?

a Virus destroy and modify user data

b Virus is a standalone program

c Virus is a code embedded in a legitimate program

d Virus cannot be detected

Medium

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465

What is known as masquerading?

a When one participant in communication pretends to be someone else

b When attacker modifies data in communication

c When attack is of fraudulent repeat of a valid data

d When attack gains access to remote systems

Medium

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466

Who unleashed famous worm attack in 1988 which effected UNIX systems and caused losses in millions?

a Robert Morris

b Bob Milano

c Mark zuckerberg

d Bill Gates

Medium

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467

What is port scanning?

a It is a software used to scan system for attack

b It is a software application designed to probe a server or host for open ports

c It is software used to scan system for introducing attacks by brute force

d None of the mentioned

Medium

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468

Which is not a port scan type?

a TCP scanning

b SYN scanning

c UDP scanning

d SYSTEM Scanning

Medium

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469

Which is not a valid port scan type?

a ACK scanning

b Window scanning

c IGMP scan

d FIN scanning

Medium

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470

What is known as a DOS attack?

a It is attacked to block traffic of network

b It is attacked to harm contents stored in HDD by worm spawn processes

c It is an attempt to make a machine or network resource unavailable

d None of the mentioned

Medium

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471

With regard to DOS attack what is not true from below options?

a We can stop DOS attack completely

b By upgrading OS vulnerability we can stop DOS attack to some extent

c DOS attack has to be stopped at network level

d Such attack can last for hours

Medium

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472

What is not an important part of security protection?

a Large amount of RAM to support antivirus

b Strong passwords

c Audit log periodically

d Scan for unauthorized programs in system directories

Medium

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473

What is used to protect network from outside internet access?

a A trusted antivirus

b 24 hours scanning for virus

c Firewall to separate trusted and untrusted network

d Deny users access to websites which can potentially cause security leak

Medium

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474

What is the best practice in the firewall domain environment?

a Create two domain trusted and untrusted domain

b Create strong policy in firewall to support different types of users

c Create a Demilitarized zone

d Create two DMZ zones with one untrusted domain

Medium

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475

Which direction access cannot happen using DMZ zone by default?

a Company computer to DMZ

b Internet to DMZ

c Internet to company computer

d Company computer to internet

Medium

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476

What are the two features of a tripwire file system?

a It is a tool to monitor file systems

b It is used to automatically take corrective action

c It is used to secure UNIX system

d None of the mentioned

Medium

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477

How do viruses avoid basic pattern match of antivirus?

a They are encrypted

b They act with special permissions

c They modify themselves

d None of the mentioned

Medium

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478

What is known as a sandbox?

a It is a program which can be molded to do the desired task

b It is a program that is controlled or emulated section of OS

c It is a special mode of antivirus

d None of the mentioned

Medium

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479

What is are two safe computing practices?

a Not to open software from unknown vendors

b Open and execute programs in admin level/root

c Open and execute programs in presence of antivirus

d None of the mentioned

Medium

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480

What are the different ways to intrude?

a Buffer overflows

b Unexpected combinations and unhandled input

c Race conditions

d All of the mentioned

Medium

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481

What are the major components of the intrusion detection system?

a Analysis Engine

b Event provider

c Alert Database

d All of the mentioned

Medium

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482

What are the different ways to classify an IDS?

a anomaly detection

b signature based misuse

c stack based

d all of the mentioned

Medium

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483

What are the different ways to classify an IDS?

a Zone based

b Host & Network based

c Network & Zone based

d Level based

Medium

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484

What are the characteristics of anomaly based IDS?

a It models the normal usage of network as a noise characterization

b It doesn’t detect novel attacks

c Anything distinct from the noise is not assumed to be intrusion activity

d It detects based on signature

Medium

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485

What is the major drawback of anomaly detection IDS?

a These are very slow at detection

b It generates many false alarms

c It doesn’t detect novel attacks

d None of the mentioned

Medium

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486

What are the drawbacks of signature based IDS?

a They are unable to detect novel attacks

b They suffer from false alarms

c They have to be programmed again for every new pattern to be detected

d All of the mentioned

Medium

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487

What are the characteristics of Host based IDS?

a The host operating system logs in the audit information

b Logs includes logins,file opens and program executions

c Logs are analysed to detect tails of intrusion

d All of the mentioned

Medium

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488

What are the drawbacks of the host based IDS?

a Unselective logging of messages may increase the audit burdens

b Selective logging runs the risk of missed attacks

c They are very fast to detect

d They have to be programmed for new patterns

Medium

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489

What are the strengths of the host based IDS?

a Attack verification

b System specific activity

c No additional hardware required

d All of the mentioned

Medium

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490

What are characteristics of stack based IDS?

a They are integrated closely with the TCP/IP stack and watch packets

b The host operating system logs in the audit information

c It is programmed to interpret a certain series of packets

d It models the normal usage of network as a noise characterization

Medium

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491

What are characteristics of Network based IDS?

a They look for attack signatures in network traffic

b Filter decides which traffic will not be discarded or passed

c It is programmed to interpret a certain series of packet

d It models the normal usage of network as a noise characterization

Medium

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492

What is the preferred way of encryption?

a pre shared secret key

b using key distribution center (KDC)

c public key-encryption

d symmetric key

Medium

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493

What is not a role of encryption?

a It is used to protect data from unauthorized access during transmission

b It is used to ensure user authentication

c It is used to ensure data integrity

d It is used to ensure data corruption doesn’t happens

Medium

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494

What is cipher-block chaining?

a Data is logically ‘ANDed’ with previous block

b Data is logically ‘ORed’ with previous block

c Data is logically ‘XORed’ with previous block

d None of the mentioned

Medium

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495

What is not an encryption standard?

a AES

b TES

c Triple DES

d DES

Medium

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496

Which of the following is not a stream cipher?

a Two fish

b RC5

c RC4

d TBONE

Medium

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497

What is a Hash Function?

a It creates a small flexible block of data

b It creates a small,fixed block of data

c It creates a encrypted block of data

d None of the mentioned

Medium

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498

SHA-1 produces __________ bit of hash.

a 128

b 160

c 150

d 112

Medium

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499

Which two of the following are authentication algorithms?

a MAC

b AES

c DAS

d Digital-signature

Medium

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500

What is the role of Key Distribution Center?

a It is used to distribute keys to everyone in world

b It intended to reduce the risks inherent in exchanging keys

c All of the mentioned

d None of the mentioned

Medium

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