Computer Science/IT MCQs
Topic Notes: Computer Science/IT
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
101
What is the fundamental purpose of a network firewall?
Answer:
To act as a barrier between a trusted internal network and an untrusted external network, like the internet.
A firewall serves as a security guard for a network. It inspects incoming and outgoing traffic and decides whether to allow or block specific traffic based on a defined set of security rules.
102
The main benefit of a signature-based detection method is:
Answer:
Its low rate of false positives and high accuracy for known attacks.
Signature-based detection is very effective at spotting known threats. Because it is looking for a specific, known pattern, it is highly accurate and is unlikely to mistakenly flag legitimate traffic (low false positives). Its weakness is its inability to detect new threats.
103
In a Public Key Infrastructure (PKI), what is the role of a Certificate Authority (CA)?
Answer:
To act as a trusted third party that issues and validates digital certificates.
A Certificate Authority is a trusted entity that binds a public key to a specific identity (a person, a company, a website). It does this by issuing a digital certificate, which you can think of as a digital passport, that vouches for the authenticity of the public key.
104
What is a potential disadvantage of an anomaly-based IDS?
Answer:
It can generate a high number of "false positives" if the definition of "normal" is not well-tuned.
The main challenge with anomaly-based systems is defining what is "normal." If a legitimate but unusual activity occurs (like a large, one-time data transfer), the system might flag it as an attack, creating a false positive alert that security staff must investigate.
105
What is a "pass-the-hash" attack?
Answer:
A technique that allows an attacker to authenticate to a remote server by using the stored hash of a user's password, without needing the plaintext password itself.
In many systems, password hashes (not the plaintext passwords) are used for authentication. If an attacker can steal this hash from a compromised system, they can reuse it to authenticate to other systems on the network as that user, bypassing the need to crack the password.
106
The Budapest Convention on Cybercrime is significant because it is:
Answer:
The first international treaty seeking to address computer crime by harmonizing national laws and improving international cooperation.
The Budapest Convention is a crucial international agreement that provides a framework for countries to develop compatible laws against cybercrime and to establish procedures for international police and judicial cooperation on cybercrime matters.
107
Which cryptographic technique transforms readable information into an unreadable format to safeguard it from unauthorized viewing?
Answer:
Encryption
Encryption is the primary method used to secure data by converting legible plaintext into an unintelligible form called ciphertext. This transformation uses an algorithm and a cryptographic key. The purpose is to protect the confidentiality of the data, ensuring that only individuals with the correct decryption key can revert the ciphertext back into its original, readable plaintext form. Encoding, while also a transformation, is typically used for data formatting or transmission and is not primarily for security against unauthorized access. Decryption is the reverse process of encryption. Hashing is used for data integrity verification, not for making data unreadable and reversible.
108
A "stateful" firewall is more advanced than a packet-filtering firewall because it:
Answer:
Keeps track of the state of active network connections.
A stateful firewall maintains a "state table" of all open connections. This allows it to make more intelligent decisions. For example, it can allow return traffic that is part of an already established connection from the inside, without needing a specific rule for it, while blocking unsolicited inbound traffic.
109
What is the main purpose of encryption?
Answer:
To convert data into a coded format (ciphertext) to prevent unauthorized access.
Encryption is the process of scrambling data (plaintext) into an unreadable format (ciphertext) using a key. Only someone with the correct key can decrypt the data back into its original, readable form, ensuring its confidentiality.
110
The Payment Card Industry Data Security Standard (PCI DSS) is a set of security standards designed to:
Answer:
Secure credit and debit card transactions against data theft and fraud.
PCI DSS is a standard that applies to any organization that accepts, transmits, or stores cardholder data. It was created by the major payment card brands (Visa, MasterCard, etc.) to reduce credit card fraud.