SECAI Core · phase 13 of 15 · noun
Intrusion detection system
A security appliance or software that analyzes data from a packet sniffer to identify traffic that violates policies or rules. Also called a network intrusion detection system (NIDS).
The Explain card
- Plain English
- An IDS is an appliance or software that inspects captured network traffic and flags activity that breaks policies or rules. The network flavour is often called a NIDS.
- Example
- An IDS watching the segment hosting an AI inference cluster alerts when a workstation begins transferring gigabytes of model weights to an external address over an unusual port.
- Why it matters
- AI infrastructure runs on ordinary networks, and model theft, data exfiltration and lateral movement all leave traffic behind. An IDS gives defenders eyes on that traffic without sitting inline.
- Hook
- The smoke detector of the network: it warns, it does not put out the fire.
Word knowledge
How the word is built, where it came from, and what it sits beside in memory.
In a sentence
A network engineer connects the intrusion detection system to a switch mirror port and reviews its alert after a port scan.
Why these words
- intrusion Latin intrudere, to thrust in names the unauthorized entry or activity being noticed
- detection Latin detegere, to uncover names the act of discovering or recognizing something
- system Greek systēma, organized whole identifies the coordinated hardware or software
Where it came from
- Origin
- an English technical compound built from Latin-derived intrusion and detection with Greek-derived system
- Entered the language
- 1980s
- What changed
- The older words for entering, uncovering, and an organized whole became a fixed computing-security phrase.
How it is spelled
- Pattern
- The phrase is written as three separate words without hyphens.
- Pattern
- Detection keeps the suffix -tion, which forms a noun from detect.
Spelled like
- intrusion prevention system
- fire detection system
- anomaly detection system
Broken into chunks
-
intrus
- intrude
- intrusive
-
detect
- detective
- detectable
-
system
- systematic
- ecosystem
What it sits beside
Same subject
- packet sniffer
- firewall
- security information and event management
- intrusion prevention system
Same shape
- intrusion prevention system
- anomaly detection system
- threat detection system
network security monitoring tools
- intrusion detection system
- packet analyzer
- network traffic analyzer
security abbreviations
- IDS
- NIDS
- IPS
- SIEM
Where it sits in the deck
Phase 13: Detection, Monitoring, and Threat Intelligence
Defences eventually fail — learn how to detect, correlate, and investigate anomalies in real time across both AI-specific and traditional security telemetry.
