Cybersecurity Key Concepts: PKI, Encryption, OSI Layers, and Network Security

Public Key Infrastructure (PKI) relies on what two things for secure communications?

Secrecy of private keys and trust in Certification Authorities (CAs)

ASCII representation of lowercase "a" (hex, decimal, binary)

61h, 97d, 01100001b

What is the purpose of a DMZ?

To segment public-facing servers from the internal network for security

Asymmetric encryption provides what security property?

Non-repudiation

Wireshark display filter for traffic to or from IP 192.168.1.1

ip.addr == 192.168.1.1

What is a collision attack?

When two different inputs produce the same hash value

Can a collision attack reveal the original plaintext?

No

Which OSI layer handles encryption?

Presentation Layer (Layer 6)

Why is Asset Management important in cybersecurity?

You cannot protect what you do not know you possess

What is defense-in-depth?

A layered security approach using multiple security controls

Example of layered defense

Adding IDS and employee security training along with firewall and antivirus

Risk of unauthorized personal devices on corporate network Creates:

a backdoor into the network

Linux command to view active network connections:

netstat

Command to run commands with administrative privileges:

sudo

What is encryption?

Converting plaintext into unreadable ciphertext using a key

Which OSI layer routes packets between networks?

Network Layer (Layer 3)

Purpose of the NIST Cybersecurity Framework (CSF)

To provide guidelines for managing cybersecurity risks

What should you do with suspicious email attachments?

Report to IT/security without opening

Principle of Least Privilege definition

Users get only the minimum access needed for their role

Does UDP guarantee reliable delivery?

No

Protocol that resolves IP addresses to MAC addresses

ARP (Address Resolution Protocol)

Protocol that dynamically assigns IP addresses

DHCP (Dynamic Host Configuration Protocol)

Primary use of Kali Linux

Penetration testing and security auditing

Security principle that limits access to necessary permissions

Principle of Least Privilege (PoLP)

Which CIA triad principle prevents unauthorized access?

Confidentiality

Example of confidentiality violation

Unauthorized access to payroll data

What does PR.AA in NIST CSF Protect function include?

Identity management, authentication, and access control

Example of PR.AA implementation

Multi-Factor Authentication (MFA)

What is reasonable assurance in cybersecurity?

Adequate security proportional to risk and cost

Best choice under reasonable assurance principle

Cost-effective protection against most likely threats

Smart speaker security best practice during sensitive conversations

Mute microphone or unplug device

What does IDS do?

Monitors network traffic for suspicious activity

Difference between TCP and UDP TCP is reliable;

UDP is not reliable

What does ASCII represent?

Characters as numeric codes computers can understand

What is non-repudiation?

Prevents sender from denying sending a message

What is a private key used for?

Decryption and digital signatures

What is a public key used for?

Encryption and signature verification