Computer Security Exam Notes

Confidentiality

Only those authorized can see the data, involving proving access and identity.

Integrity

Ensures data is not modified by unauthorized sources and can be verified from the origin.

Availability

Systems and services are accessible and resilient against attacks, failures, and compromises.

Threat

Something that can cause harm to a system or data.

Vulnerability

A weakness in a system that can be exploited to cause harm.

Risk

The possibility of a threat occurring, varying based on known vulnerabilities and system exposure.

Symmetric Encryption

Uses the same key for both encryption and decryption, faster than asymmetric.

Asymmetric Encryption

Uses a public key for encryption and a private key for decryption; slower but enables secure key exchanges.

Salt

A random value added to passwords before hashing to protect against attacks; stored alongside the hash.

Encoding

Transforms data into a different format but does not secure it; not the same as encryption.

PBKDF2

Used for password hashing and key derivation; differs from AES which encrypts data.

Digital Signature

Verifies authentication and integrity of messages using asymmetric encryption.

CA (Certificate Authority)

Issues and verifies digital certificates.

Root CA

A self-signed CA that acts as the trust anchor.

TLS (Transport Layer Security)

Uses certificates to secure communication between a client and server.

TCP SYN Flood

An attack where an attacker overwhelms a server by sending numerous SYN requests.

TCP (Transmission Control Protocol)

Ensures reliable communication between devices.

IP (Internet Protocol)

Routes packets between networks, identifying devices with IP addresses.

DMZ (Demilitarized Zone)

A network zone where public-facing servers are placed, typically protected by firewalls.

Whois

A tool used to find domain ownership information.

NMAP

A network scanning tool used to identify open ports and services.

DNS (Domain Name System)

Maps domain names to IP addresses, vulnerable to attacks like DNS poisoning.

Principle of Least Privilege

Users and processes should have the minimum permissions necessary.

Malware

Any malicious software that can harm a device or network.

Virus

Malicious software that attaches itself to files and spreads when the file is executed.

Trojan

Malicious software that disguises itself as legitimate software to trick users into installing it.

Spyware

Software that collects user data without consent, often monitoring activities or stealing information.

Phishing

A cyber attack that tricks users into revealing personal information through fraudulent means, such as fake login pages.

Packet Filtering Firewall

Examines packets individually and filters traffic based on predefined security rules.

Stateful Inspection Firewall

Tracks active connections and makes filtering decisions based on the state of the connection.

Operating System Hardening

The process of securing an operating system by reducing its surface of vulnerability.

Service Limitation in Hardening

Ensuring that only necessary services and software are running to minimize potential attack vectors.

What is hashing and what are its uses?

Hashing converts input data into a fixed-size, seemingly random string and is used for password storage, data integrity, and as a non-reversible function.

How can hash tables be attacked and what solutions exist?

Hash tables are vulnerable to attacks like rainbow tables for cracking passwords. To defend against this, use salts for password storage and strong hashing algorithms like SHA-256 and SHA-2, avoiding weaker ones like MD5 and SHA-1.