Common Network Threats — A Defender's Overview

Recognise the common threat categories a network engineer is expected to defend against.

beginnernetwork-securityfundamentalsthreats

What is it?

A network security threat is anything that can compromise confidentiality, integrity or availability of data on the network. As a defender, you do not need to know how to build these attacks — you need to recognise the pattern and know which control stops it.

Why should I learn it?

Interviewers regularly ask “how would you detect or stop X?” for common threats. Knowing the category and the matching defensive control is what separates a job-ready answer from a textbook definition.

How it works

Threat categoryWhat it targetsTypical defensive control
Phishing / social engineeringPeople, credentialsEmail filtering, MFA, awareness training
MalwareEndpoints, availabilityEndpoint protection, segmentation
Man-in-the-middle (MITM)Confidentiality/integrity of trafficEncryption (VPN/TLS), port security, DAI
Denial of Service (DoS)AvailabilityRate limiting, upstream DDoS protection
Unauthorised accessConfidentialityFirewalls, ACLs, AAA

Real-world example

ARP spoofing (a MITM technique covered in the Networking section) is stopped at the switch level using Dynamic ARP Inspection — a network security control, not an endpoint one.

Troubleshooting mindset

When investigating unusual traffic, first classify which category it fits, then ask which layer (endpoint, network, or perimeter) is the right place to control it.

Common mistake

Do not memorise the definition without connecting it to packet flow, device state and verification. Ask: what should happen, what actually happened, and which command or capture can prove the difference?

Quick recap

  • Understand the job of the protocol or feature.
  • Know where it sits in the traffic path.
  • Verify behaviour instead of guessing.
  • Connect the topic to the next networking layer.

Interview connection

Explain the concept in simple words first. Then give one practical example or troubleshooting check. That is stronger than repeating a textbook definition.

References & Further Reading

  • AddySec original content — written for the Network Security track to build practical, interview-ready understanding.
CONTINUE LEARNING